Finalist: Staff of The New York Times

By Chris Buckley and Paul Mozur

KASHGAR, China — A God’s-eye view of Kashgar, an ancient city in western China, flashed onto a wall-size screen, with colorful icons marking police stations, checkpoints and the locations of recent security incidents. At the click of a mouse, a technician explained, the police can pull up live video from any surveillance camera or take a closer look at anyone passing through one of the thousands of checkpoints in the city.

To demonstrate, she showed how the system could retrieve the photo, home address and official identification number of a woman who had been stopped at a checkpoint on a major highway. The system sifted through billions of records, then displayed details of her education, family ties, links to an earlier case and recent visits to a hotel and an internet cafe.

The simulation, presented at an industry fair in China, offered a rare look at a system that now peers into nearly every corner of Xinjiang, the troubled region where Kashgar is located.

This is the vision of high-tech surveillance — precise, all-seeing, infallible — that China’s leaders are investing billions of dollars in every year, making Xinjiang an incubator for increasingly intrusive policing systems that could spread across the country and beyond.

It is also a vision that some of President Trump’s aides have begun citing in a push for tougher action against Chinese companies in the intensifying trade war. Beyond concerns about market barriers, theft and national security, they argue that China is using technology to strengthen authoritarianism at home and abroad — and that the United States must stop it.

Developed and sold by the China Electronics Technology Corporation, a state-run defense manufacturer, the system in Kashgar is on the cutting edge of what has become a flourishing new market for technology that the government can use to monitor and subdue millions of Uighurs and members of other Muslim ethnic groups in Xinjiang.

Treating a city like a battlefield, the platform was designed to “apply the ideas of military cyber systems to civilian public security,” Wang Pengda, a C.E.T.C. engineer, said in an official blog post. “Looking back, it truly was an idea ahead of its time.”

The system taps into networks of neighborhood informants; tracks individuals and analyzes their behavior; tries to anticipate potential crime, protest or violence; and then recommends which security forces to deploy, the company said.

On the screen during the demonstration was a slogan: “If someone exists, there will be traces, and if there are connections, there will be information.”

A New York Times investigation drawing on government and company records as well as interviews with industry insiders found that China is in effect hard-wiring Xinjiang for segregated surveillance, using an army of security personnel to compel ethnic minorities to submit to monitoring and data collection while generally ignoring the majority Han Chinese, who make up 36 percent of Xinjiang’s population.

It is a virtual cage that complements the indoctrination camps in Xinjiang where the authorities have detained a million or more Uighurs and other Muslims in a push to transform them into secular citizens who will never challenge the ruling Communist Party. The program helps identify people to be sent to the camps or investigated, and keeps tabs on them when they are released.

The Trump administration is considering whether to blacklist one of the Chinese companies at the center of the Xinjiang effort, Hikvision, and bar it from buying American technology. Hikvision is a major manufacturer of video surveillance equipment, with customers around the world and across Xinjiang, where its cameras have been installed at mosques and detention camps. C.E.T.C. owns about 42 percent of the company through subsidiaries.

“Xinjiang is maybe a kind of more extreme, more intrusive example of China’s mass surveillance systems,” said Maya Wang, a China researcher for Human Rights Watch who has studied the technology in the region. “These systems are designed for a very explicit purpose — to target Muslims.”

Virtual fences

In the city of Kashgar, with a population of 720,000 — about 85 percent of them Uighur — the C.E.T.C. platform draws on databases with 68 billion records, including those on people’s movements and activities, according to the demonstration viewed by a Times reporter at the industry fair, held in the eastern city of Wuzhen in late 2017.

By comparison, the F.B.I.’s national instant criminal background check system contained about 19 million records at the end of 2018.

The police in Xinjiang use a mobile app, made by C.E.T.C. for smartphones running the Android operating system, to enter information into the databases.

Human Rights Watch, which obtained and analyzed the app, said it helped the authorities spot behavior that they consider suspicious, including extended travel abroad or the use of an “unusual” amount of electricity.

The app, which the Times examined, also allows police officers to flag people they believe have stopped using a smartphone, have begun avoiding the use of the front door in coming and going from home, or have refueled someone else’s car.

The police use the app at checkpoints that serve as virtual “fences” across Xinjiang. If someone is tagged as a potential threat, the system can be set to trigger an alarm every time he or she tries to leave the neighborhood or enters a public place, Human Rights Watch said.

“The government’s arbitrary power is reflected, or coded, in the app,” Ms. Wang said, adding that the system “is programmed to consider vague, broad categories of behaviors, many of them perfectly legal, as indicators of suspiciousness.”

Intelligence agencies in many countries use sets of behavior to single out individuals for greater scrutiny. But China has taken that approach to an extreme, treating the Muslim population in Xinjiang as suspect from the start and defining suspicious behavior in sweeping terms, including peaceful religious activities such as making a donation to a mosque.

The Chinese government has defended the surveillance program, saying it has improved security in the region, and says the indoctrination camps in Xinjiang are job training centers. Hikvision has denied “any inappropriate actions in Xinjiang,” and C.E.T.C. declined to comment when reached by phone.

C.E.T.C. traces its roots to the military research labs that helped build China’s first nuclear bomb, satellite and guided missile. Established as a state defense manufacturer in 2002, it soon expanded into civilian security matters, working with Microsoft, for instance, to create a version of Windows that meets the government’s internal security requirements.

In recent years, it turned to Xinjiang.

The Communist Party, which took control of the region in 1949, has long been wary of the Uighurs, whose Turkic culture and Muslim faith have inspired demands for self-rule, and sometimes attacks on Chinese targets. State investment in surveillance took off a decade ago after anti-Chinese rioting in the regional capital, Urumqi, killed nearly 200 people.

The real bonanza of security contracts came after Xi Jinping took the helm of the party in late 2012. Spending on internal security in Xinjiang totaled nearly $8.4 billion in 2017, six times as much as in 2012, including funds for surveillance, personnel and the indoctrination camps.

Hikvision has received contracts in Xinjiang worth at least $290 million for its cameras and facial recognition systems. Another company tapping into Xinjiang’s security gold rush is Huawei, the Chinese tech giant that the United States has described as a security threat. It signed an agreement last year with the region’s police department to help officers analyze data.

‘The goal here is instilling fear’

The multilayered program to harvest information from Uighurs and other Muslims begins on the edges of towns and cities across Xinjiang in buildings that look like toll plazas.

Instead of coins, they collect personal information.

On a recent visit to one checkpoint in Kashgar, a line of passengers and drivers, nearly all Uighur, got out of their vehicles, trudged through automated gates made by C.E.T.C. and swiped their identity cards.

“Head up,” the machines chimed as they photographed the motorists and armed guards looked on.

There are smaller checkpoints at banks, parks, schools, gas stations and mosques, all recording information from identity cards in the mass surveillance database.

Identification cards are also needed to buy knives, gasoline, phones, computers and even sugar. The purchases are entered into a police database used to flag suspicious behavior or individuals, according to a 2017 dissertation by a researcher at the Chinese Academy of Sciences that features screenshots of the system in Kashgar.

Not everyone has to endure the inconvenience. At many checkpoints, privileged groups — Han Chinese, Uighur officials with passes, and foreign visitors — are waved through “green channels.” In this way, the authorities have created separate yet overlapping worlds on the same streets — and in the online police databases — one for Muslim minorities, the other for Han Chinese.

“The goal here is instilling fear — fear that their surveillance technology can see into every corner of your life,” said Wang Lixiong, a Chinese author who has written about Xinjiang as well as China’s surveillance state. “The amount of people and equipment used for security is part of the deterrent effect.”

A database stored online by SenseNets, a Chinese surveillance company, and examined by the Times suggests the scale of surveillance in Xinjiang: It contained facial recognition records and ID scans for about 2.5 million people, mostly in Urumqi, a city with a population of about 3.5 million.

“This can be pulled off by anyone, and that’s the part that worries me,” said Victor Gevers, a Dutch security researcher and co-founder of GDI Foundation, a nonprofit that promotes internet security.

According to Mr. Gevers, who discovered the unsecured database, the online records indicate that a network of about 10,000 checkpoints in Urumqi made more than six million identifications in 24 hours.

The authorities in Xinjiang also sometimes force residents to install an app known as “Clean Net Guard” on their phones to monitor for content that the government deems suspicious.

Kashgar and other areas of Xinjiang have in recent years systematically collected DNA and other biological data from residents too, especially Muslims. Officials now collect blood, fingerprints, voice recordings, head portraits from multiple angles, and scans of irises, which can provide a unique identifier like fingerprints.

These databases are not yet completely integrated, and despite the futuristic gloss of the Xinjiang surveillance state, the authorities rely on hundreds of thousands of police officers, officials and neighborhood monitors to gather and enter data.

“We risk understating the extent to which this high-tech police state continues to require a lot of manpower,” said Adrian Zenz, an independent researcher who has studied security spending in Xinjiang. “It is the combination of manpower and technology that makes the 21st-century police state so powerful.”

Expanding beyond the region

Xinjiang’s security and surveillance systems are already attracting admirers from the rest of China. Delegations of police officers from other provinces and cities have visited Kashgar and other cities to admire — and consider adopting — the measures.

They often visit police command centers where rows of officers peer at computers, scanning surveillance video feeds and information on residents on the C.E.T.C. platform.

“The digitalization of police work has achieved leap-like growth in Xinjiang,” Zhang Ping, a counterterrorism officer from Jiujiang, a city in southeastern China, said during a visit to Xinjiang last year, according to an official report on the website of the city’s police bureau.

Xinjiang’s high-tech policing, he added, was “something we should vigorously study.”

Zhejiang and Guangdong, two wealthy provinces on China’s southeastern coast, have been testing the C.E.T.C. surveillance system used in Xinjiang, “laying a robust foundation for a nationwide rollout,” the company said last year.

C.E.T.C. has also signed an agreement with the police in the southern city of Shenzhen to provide an advanced “command center information system” similar to the one in Xinjiang.

The technology has some way to go. Dust and bad lighting can hobble facial recognition on security cameras, which struggle to track large numbers of people simultaneously. Even the best systems can be accurate in less than 20 percent of cases, according to one study published by a journal linked to the Ministry of Public Security.

A technician who until recently installed and maintained computers for the authorities in Xinjiang said police surveillance centers relied on hundreds of workers to monitor cameras, an expensive and inefficient undertaking.

And outside urban centers, police officers often do not have the skills to operate the sophisticated systems, said the technician, who spoke on the condition of anonymity, fearing repercussions for speaking to a journalist.

The spending spree on security in Xinjiang has left local governments across the region with staggering bills, raising questions about how the authorities can keep the systems running.

In Kashgar, for example, the county of Yengisar warned this year of a “huge shortfall” from spending on security and said that it had accumulated 1 billion renminbi, or about $150 million, in previously undeclared “invisible debt.”

“The pressure from ensuring basic spending for additional staff and to maintain stability is extraordinary,” it said.

Still, the region’s leaders told officials this year that they must not wind back spending.

“Preserving stability is a hard-and-fast task that takes priority over everything else,” the leadership said in the region’s annual budget report. “Use every possible means to find funds so that the high-pressure offensive does not let up.”

Austin Ramzy contributed reporting from Hong Kong, and Aaron Krolik from New York.

In Xinjiang the authorities have separated nearly half a million children from their families, aiming to instill loyalty to China and the Communist Party.

By Amy Qin

HOTAN, China — The first grader was a good student and beloved by her classmates, but she was inconsolable, and it was no mystery to her teacher why.

“The most heartbreaking thing is that the girl is often slumped over on the table alone and crying,” he wrote on his blog. “When I asked around, I learned that it was because she missed her mother.”

The mother, he noted, had been sent to a detention camp for Muslim ethnic minorities. The girl’s father had passed away, he added. But instead of letting other relatives raise her, the authorities put her in a state-run boarding school — one of hundreds of such facilities that have opened in China’s far western Xinjiang region.

As many as a million ethnic Uighurs, Kazakhs and others have been sent to internment camps and prisons in Xinjiang over the past three years, an indiscriminate clampdown aimed at weakening the population’s devotion to Islam. Even as these mass detentions have provoked global outrage, though, the Chinese government is pressing ahead with a parallel effort targeting the region’s children.

Nearly a half million children have been separated from their families and placed in boarding schools so far, according to a planning document published on a government website, and the ruling Communist Party has set a goal of operating one to two such schools in each of Xinjiang’s 800-plus townships by the end of next year.

The party has presented the schools as a way to fight poverty, arguing that they make it easier for children to attend classes if their parents live or work in remote areas or are unable to care for them. And it is true that many rural families are eager to send their children to these schools, especially when they are older.

But the schools are also designed to assimilate and indoctrinate children at an early age, away from the influence of their families, according to the planning document, published in 2017. Students are often forced to enroll because the authorities have detained their parents and other relatives, ordered them to take jobs far from home or judged them unfit guardians.

The schools are off limits to outsiders and tightly guarded, and it is difficult to interview residents in Xinjiang without putting them at risk of arrest. But a troubling picture of these institutions emerges from interviews with Uighur parents living in exile and a review of documents published online, including procurement records, government notices, state media reports and the blogs of teachers in the schools.

State media and official documents describe education as a key component of President Xi Jinping’s campaign to wipe out extremist violence in Xinjiang, a ruthless and far-reaching effort that also includes the mass internment camps and sweeping surveillance measures. The idea is to use the boarding schools as incubators of a new generation of Uighurs who are secular and more loyal to both the party and the nation.

“The long-term strategy is to conquer, to captivate, to win over the young generation from the beginning,” said Adrian Zenz, a researcher at the Victims of Communism Memorial Foundation in Washington who has studied Chinese policies that break up Uighur families.

To carry out the assimilation campaign, the authorities in Xinjiang have recruited tens of thousands of teachers from across China, often Han Chinese, the nation’s dominant ethnic group. At the same time, prominent Uighur educators have been imprisoned and teachers have been warned they will be sent to the camps if they resist.

Thrust into a regimented environment and immersed in an unfamiliar culture, children in the boarding schools are only allowed visits with family once every week or two — a restriction intended to “break the impact of the religious atmosphere on children at home,” in the words of the 2017 policy document.

The campaign echoes past policies in Canada, the United States and Australia that took indigenous children from their families and placed them in residential schools to forcibly assimilate them.

“The big difference in China is the scale and how systematic it is,” said Darren Byler, an anthropologist at the University of Colorado who studies Uighur culture and society.

Public discussion in China of the trauma inflicted on Uighur children by separating them from their families is rare. References on social media are usually quickly censored. Instead, the state-controlled news media focuses on the party’s goals in the region, where predominantly Muslim minorities make up more than half the population of 25 million.

Visiting a kindergarten near the frontier city of Kashgar this month, Chen Quanguo, the party’s top official in Xinjiang, urged teachers to ensure children learn to “love the party, love the motherland and love the people.”

Indoctrinating Children

Abdurahman Tohti left Xinjiang and immigrated to Turkey in 2013, leaving behind cotton farming to sell used cars in Istanbul. But when his wife and two young children returned to China for a visit a few years ago, they disappeared.

He heard that his wife was sent to prison, like many Uighurs who have traveled abroad and returned to China. His parents were detained too. The fate of his children, though, was a mystery.

Then in January, he spotted his 4-year-old son in a video on Chinese social media that had apparently been recorded by a teacher. The boy seemed to be at a state-run boarding school and was speaking Chinese, a language his family did not use.

Mr. Tohti, 30, said he was excited to see the child, and relieved he was safe — but also gripped by desperation.

“What I fear the most,” he said, “is that the Chinese government is teaching him to hate his parents and Uighur culture.”

Beijing has sought for decades to suppress Uighur resistance to Chinese rule in Xinjiang, in part by using schools in the region to indoctrinate Uighur children. Until recently, though, the government had allowed most classes to be taught in the Uighur language, partly because of a shortage of Chinese-speaking teachers.

Then, after a surge of antigovernment and anti-Chinese violence, including ethnic riots in 2009 in Urumqi, the regional capital, and deadly attacks by Uighur militants in 2014, Mr. Xi ordered the party to take a harder line in Xinjiang, according to internal documents leaked to The New York Times earlier this year.

In December 2016, the party announced that the work of the region’s education bureau was entering a new phase. Schools were to become an extension of the security drive in Xinjiang, with a new emphasis on the Chinese language, patriotism and loyalty to the party.

In the 2017 policy document, posted on the education ministry’s website, officials from Xinjiang outlined their new priorities and ranked expansion of the boarding schools at the top.

Without specifying Islam by name, the document characterized religion as a pernicious influence on children, and said having students live at school would “reduce the shock of going back and forth between learning science in the classroom and listening to scripture at home.”

By early 2017, the document said, nearly 40 percent of all middle-school and elementary-school age children in Xinjiang — or about 497,800 students — were boarding in schools. At the time, the government was ramping up efforts to open boarding schools and add dorms to schools, and more recent reports suggest the push is continuing.

Chinese is also replacing Uighur as the main language of instruction in Xinjiang. Most elementary and middle school students are now taught in Chinese, up from just 38 percent three years ago. And thousands of new rural preschools have been built to expose minority children to Chinese at an earlier age, state media reported.

The government argues that teaching Chinese is critical to improving the economic prospects of minority children, and many Uighurs agree. But Uighur activists say the overall campaign amounts to an effort to erase what remains of their culture.

Several Uighurs living abroad said the government had put their children in boarding schools without their consent.

Mahmutjan Niyaz, 33, a Uighur businessman who moved to Istanbul in 2016, said his 5-year-old daughter was sent to one after his brother and sister-in-law, the girl’s guardians, were confined in an internment camp.

Other relatives could have cared for her but the authorities refused to let them. Now, Mr. Niyaz said, the school has changed the girl.

“Before, my daughter was playful and outgoing,” he said. “But after she went to the school, she looked very sad in the photos.”

‘Kindness Students’

In a dusty village near the ancient Silk Road city of Hotan in southern Xinjiang, nestled among fields of barren walnut trees and simple concrete homes, the elementary school stood out.

It was surrounded by a tall brick wall with two layers of barbed wire on top. Cameras were mounted on every corner. And at the entrance, a guard wearing a black helmet and a protective vest stood beside a metal detector.

It wasn’t always like this. Last year, officials converted the school in Kasipi village into a full-time boarding school.

Kang Jide, a Chinese language teacher at the school, described the frenzied process on his public blog on the Chinese social media platform WeChat: In just a few days, all the day students were transferred. Classrooms were rearranged. Bunk beds were set up. Then, 270 new children arrived, leaving the school with 430 boarders, each in the sixth grade or below.

Officials called them “kindness students,” referring to the party’s generosity in making special arrangements for their education.

The government says children in Xinjiang’s boarding schools are taught better hygiene and etiquette as well as Chinese and science skills that will help them succeed in modern China.

“My heart suddenly melted after seeing the splendid heartfelt smiles on the faces of these left-behind children,” said a retired official visiting a boarding elementary school in Lop County near Hotan, according to a state media report. He added that the party had given them “an environment to be carefree, study happily, and grow healthy and strong.”

But Mr. Kang wrote that being separated from their families took a toll on the children. Some never received visits from relatives, or remained on campus during the holidays, even after most teachers left. And his pupils often begged to use his phone to call their parents.

“Sometimes, when they hear the voice on the other end of the call, the children will start crying and they hide in the corner because they don’t want me to see,” he wrote.

“It’s not just the children,” he added. “The parents on the other end also miss their children of course, so much so that it breaks their hearts and they’re trembling.”

The internment camps, which the government describes as job training centers, have cast a shadow even on students who are not boarders. Before the conversion of the school, Mr. Kang posted a photo of a letter that an 8-year-old girl had written to her father, who had been sent to a camp.

“Daddy, where are you?” the girl wrote in an uneven scrawl. “Daddy, why don’t you come back?”

“I’m sorry, Daddy,” she continued. “You must study hard too.”

Nevertheless, Mr. Kang was generally supportive of the schools. On his blog, he described teaching Uighur students as an opportunity to “water the flowers of the motherland.”

“Kindness students” receive more attention and resources than day students. Boarding schools are required to offer psychological counseling, for example, and in Kasipi, the children were given a set of supplies that included textbooks, clothes and a red Young Pioneer scarf.

Learning Chinese was the priority, Mr. Kang wrote, though students were also immersed in traditional Chinese culture, including classical poetry, and taught songs praising the party.

On a recent visit to the school, children in red and blue uniforms could be seen playing in a yard beside buildings marked “cafeteria” and “student dormitory.” At the entrance, school officials refused to answer questions.

Tighter security has become the norm at schools in Xinjiang. In Hotan alone, more than a million dollars has been allocated in the past three years to buy surveillance and security equipment for schools, including helmets, shields and spiked batons, according to procurement records. At the entrance to one elementary school, a facial recognition system had been installed.

Mr. Kang recently wrote on his blog that he had moved on to a new job teaching in northern Xinjiang. Reached by telephone there, he declined to be interviewed. But before hanging up, he said his students in Kasipi had made rapid progress in learning Chinese.

“Every day I feel very fulfilled,” he said.

‘Engineers of the Human Soul’

To carry out its campaign, the party needed not only new schools but also an army of teachers, an overhaul of the curriculum — and political discipline. Teachers suspected of dissent were punished, and textbooks were rewritten to weed out material deemed subversive.

“Teachers are the engineers of the human soul,” the education bureau of Urumqi recently wrote in an open letter, deploying a phrase first used by Stalin to describe writers and other cultural workers.

The party launched an intensive effort to recruit teachers for Xinjiang from across China. Last year, nearly 90,000 were brought in, chosen partly for their political reliability, officials said at a news conference this year. The influx amounted to about a fifth of Xinjiang’s teachers last year, according to government data.

The new recruits, often ethnic Han, and the teachers they joined, mostly Uighurs, were both warned to toe the line. Those who opposed the Chinese-language policy or resisted the new curriculum were labeled “two-faced” and punished.

The deputy secretary-general of the oasis town of Turpan, writing earlier this year, described such teachers as “scum of the Chinese people” and accused them of being “bewitched by extremist religious ideology.”

Teachers were urged to express their loyalty, and the public was urged to keep an eye on them. A sign outside a kindergarten in Hotan invited parents to report teachers who made “irresponsible remarks” or participated in unauthorized religious worship.

Officials in Xinjiang also spent two years inspecting and revising hundreds of textbooks and other teaching material, according to the 2017 policy document.

Some who helped the party write and edit the old textbooks ended up in prison, including Yalqun Rozi, a prominent scholar and literary critic who helped compile a set of textbooks on Uighur literature that were used for more than a decade.

Mr. Rozi was charged with attempted subversion and sentenced to 15 years in prison last year, according to his son, Kamaltürk Yalqun. Several other members of the committee that compiled the textbooks were arrested too, he said.

“Instead of welcoming the cultural diversity of Uighurs, China labeled it a malignant tumor,” said Mr. Yalqun, who lives in Philadelphia.

There is evidence that some Uighur children have been sent to boarding schools far from their homes.

Kalbinur Tursun, 36, entrusted five of her children to relatives when she left Xinjiang to give birth in Istanbul but has been unable to contact them for several years.

Last year, she saw her daughter Ayshe, then 6, in a video circulating on Chinese social media. It had been posted by a user who appeared to be a teacher at a school in Hotan — more than 300 miles away from their home in Kashgar.

“My children are so young, they just need their mother and father,” Ms. Tursun said, expressing concern about how the authorities were raising them. “I fear they will think that I’m the enemy — that they won’t accept me and will hate me.”

Fatima Er contributed reporting from Istanbul.

By Sui-Lee Wee

BEIJING — The authorities called it a free health check. Tahir Imin had his doubts.

They drew blood from the 38-year-old Muslim, scanned his face, recorded his voice and took his fingerprints. They didn’t bother to check his heart or kidneys, and they rebuffed his request to see the results.

“They said, ‘You don’t have the right to ask about this,’” Mr. Imin said. “‘If you want to ask more,’ they said, ‘you can go to the police.’”

Mr. Imin was one of millions of people caught up in a vast Chinese campaign of surveillance and oppression. To give it teeth, the Chinese authorities are collecting DNA — and they got unlikely corporate and academic help from the United States to do it.

China wants to make the country’s Uighurs, a predominantly Muslim ethnic group, more subservient to the Communist Party. It has detained up to a million people in what China calls “re-education” camps, drawing condemnation from human rights groups and a threat of sanctions from the Trump administration.

Collecting genetic material is a key part of China’s campaign, according to human rights groups and Uighur activists. They say a comprehensive DNA database could be used to chase down any Uighurs who resist conforming to the campaign.

Police forces in the United States and elsewhere use genetic material from family members to find suspects and solve crimes. Chinese officials, who are building a broad nationwide database of DNA samples, have cited the crime-fighting benefits of China’s own genetic studies.

To bolster their DNA capabilities, scientists affiliated with China’s police used equipment made by Thermo Fisher, a Massachusetts company. For comparison with Uighur DNA, they also relied on genetic material from people around the world that was provided by Kenneth Kidd, a prominent Yale University geneticist.

On Wednesday, Thermo Fisher said it would no longer sell its equipment in Xinjiang, the part of China where the campaign to track Uighurs is mostly taking place. The company said separately in an earlier statement to The New York Times that it was working with American officials to figure out how its technology was being used.

Dr. Kidd said he had been unaware of how his material and know-how were being used. He said he believed Chinese scientists were acting within scientific norms that require informed consent by DNA donors.

China’s campaign poses a direct challenge to the scientific community and the way it makes cutting-edge knowledge publicly available. The campaign relies in part on public DNA databases and commercial technology, much of it made or managed in the United States. In turn, Chinese scientists have contributed Uighur DNA samples to a global database, potentially violating scientific norms of consent.

Cooperation from the global scientific community “legitimizes this type of genetic surveillance,” said Mark Munsterhjelm, an assistant professor at the University of Windsor in Ontario who has closely tracked the use of American technology in Xinjiang.

Swabbing Millions

In Xinjiang, in northwestern China, the program was known as “Physicals for All.”

From 2016 to 2017, nearly 36 million people took part in it, according to Xinhua, China’s official news agency. The authorities collected DNA samples, images of irises and other personal data, according to Uighurs and human rights groups. It is unclear whether some residents participated more than once — Xinjiang has a population of about 24.5 million.

In a statement, the Xinjiang government denied that it collects DNA samples as part of the free medical checkups. It said the DNA machines that were bought by the Xinjiang authorities were for “internal use.”

China has for decades maintained an iron grip in Xinjiang. In recent years, it has blamed Uighurs for a series of terrorist attacks in Xinjiang and elsewhere in China, including a 2013 incident in which a driver struck two people in Tiananmen Square in Beijing.

In late 2016, the Communist Party embarked on a campaign to turn the Uighurs and other largely Muslim minority groups into loyal supporters. The government locked up hundreds of thousands of them in what it called job training camps, touted as a way to escape poverty, backwardness and radical Islam. It also began to take DNA samples.

In at least some of the cases, people didn’t give up their genetic material voluntarily. To mobilize Uighurs for the free medical checkups, police and local cadres called or sent them text messages, telling them the checkups were required, according to Uighurs interviewed by The Times.

“There was a pretty strong coercive element to it,” said Darren Byler, an anthropologist at the University of Washington who studies the plight of the Uighurs. “They had no choice.”

Calling Dr. Kidd

Kenneth Kidd first visited China in 1981 and remained curious about the country. So when he received an invitation in 2010 for an expenses-paid trip to visit Beijing, he said yes.

Dr. Kidd is a major figure in the genetics field. The 77-year-old Yale professor has helped to make DNA evidence more acceptable in American courts.

His Chinese hosts had their own background in law enforcement. They were scientists from the Ministry of Public Security — essentially, China’s police.

During that trip, Dr. Kidd met Li Caixia, the chief forensic physician of the ministry’s Institute of Forensic Science. The relationship deepened. In December 2014, Dr. Li arrived at Dr. Kidd’s lab for an 11-month stint. She took some DNA samples back to China.

“I had thought we were sharing samples for collaborative research,” said Dr. Kidd.

Dr. Kidd is not the only prominent foreign geneticist to have worked with the Chinese authorities. Bruce Budowle, a professor at the University of North Texas, says in his online biography that he “has served or is serving” as a member of an academic committee at the ministry’s Institute of Forensic Science.

Jeff Carlton, a university spokesman, said in a statement that Professor Budowle’s role with the ministry was “only symbolic in nature” and that he had “done no work on its behalf.”

“Dr. Budowle and his team abhor the use of DNA technology to persecute ethnic or religious groups,” Mr. Carlton said in the statement. “Their work focuses on criminal investigations and combating human trafficking to serve humanity.”

Dr. Kidd’s data became part of China’s DNA drive.

In 2014, ministry researchers published a paper describing a way for scientists to tell one ethnic group from another. It cited, as an example, the ability to distinguish Uighurs from Indians. The authors said they used 40 DNA samples taken from Uighurs in China and samples from other ethnic groups from Dr. Kidd’s Yale lab.

In patent applications filed in China in 2013 and 2017, ministry researchers described ways to sort people by ethnicity by screening their genetic makeup. They took genetic material from Uighurs and compared it with DNA from other ethnic groups. In the 2017 filing, researchers explained that their system would help in “inferring the geographical origin from the DNA of suspects at crime scenes.”

For outside comparisons, they used DNA samples provided by Dr. Kidd’s lab, the 2017 filing said. They also used samples from the 1000 Genomes Project, a public catalog of genes from around the world.

Paul Flicek, member of the steering committee of the 1000 Genomes Project, said that its data was unrestricted and that “there is no obvious problem” if it was being used as a way to determine where a DNA sample came from.

The data flow also went the other way.

Chinese government researchers contributed the data of 2,143 Uighurs to the Allele Frequency Database, an online search platform run by Dr. Kidd that was partly funded by the United States Department of Justice until last year. The database, known as Alfred, contains DNA data from more than 700 populations around the world.

This sharing of data could violate scientific norms of informed consent because it is not clear whether the Uighurs volunteered their DNA samples to the Chinese authorities, said Arthur Caplan, the founding head of the division of medical ethics at New York University’s School of Medicine. He said that “no one should be in a database without express consent.”

“Honestly, there’s been a kind of naïveté on the part of American scientists presuming that other people will follow the same rules and standards wherever they come from,” Dr. Caplan said.

Dr. Kidd said he was “not particularly happy” that the ministry had cited him in its patents, saying his data shouldn’t be used in ways that could allow people or institutions to potentially profit from it. If the Chinese authorities used data they got from their earlier collaborations with him, he added, there is little he can do to stop them.

He said he was unaware of the filings until he was contacted by The Times.

Dr. Kidd also said he considered his collaboration with the ministry to be no different from his work with police and forensics labs elsewhere. He said governments should have access to data about minorities, not just the dominant ethnic group, in order to have an accurate picture of the whole population.

As for the consent issue, he said the burden of meeting that standard lay with the Chinese researchers, though he said reports about what Uighurs are subjected to in China raised some difficult questions.

“I would assume they had appropriate informed consent on the samples,” he said, “though I must say what I’ve been hearing in the news recently about the treatment of the Uighurs raises concerns.”

Machine Learning

In 2015, Dr. Kidd and Dr. Budowle spoke at a genomics conference in the Chinese city of Xi’an. It was underwritten in part by Thermo Fisher, a company that has come under intense criticism for its equipment sales in China, and Illumina, a San Diego company that makes gene sequencing instruments. Illumina did not respond to requests for comment.

China is ramping up spending on health care and research. The Chinese market for gene-sequencing equipment and other technologies was worth $1 billion in 2017 and could more than double in five years, according to CCID Consulting, a research firm. But the Chinese market is loosely regulated, and it isn’t always clear where the equipment goes or to what uses it is put.

Thermo Fisher sells everything from lab instruments to forensic DNA testing kits to DNA mapping machines, which help scientists decipher a person’s ethnicity and identify diseases to which he or she is particularly vulnerable. China accounted for 10 percent of Thermo Fisher’s $20.9 billion in revenue, according to the company’s 2017 annual report, and it employs nearly 5,000 people there.

“Our greatest success story in emerging markets continues to be China,” it said in the report.

China used Thermo Fisher’s equipment to map the genes of its people, according to five Ministry of Public Security patent filings.

The company has also sold equipment directly to the authorities in Xinjiang, where the campaign to control the Uighurs has been most intense. At least some of the equipment was intended for use by the police, according to procurement documents. The authorities there said in the documents that the machines were important for DNA inspections in criminal cases and had “no substitutes in China.”

In February 2013, six ministry researchers credited Thermo Fisher’s Applied Biosystems brand, as well as other companies, with helping to analyze the DNA samples of Han, Uighur and Tibetan people in China, according to a patent filing. The researchers said understanding how to differentiate between such DNA samples was necessary for fighting terrorism “because these cases were becoming more difficult to crack.”

The researchers said they had obtained 95 Uighur DNA samples, some of which were given to them by the police. Other samples were provided by Uighurs voluntarily, they said.

Thermo Fisher was criticized by Senator Marco Rubio, Republican of Florida, and others who asked the Commerce Department to prohibit American companies from selling technology to China that could be used for purposes of surveillance and tracking.

On Wednesday, Thermo Fisher said it would stop selling its equipment in Xinjiang, a decision it said was “consistent with Thermo Fisher’s values, ethics code and policies.”

“As the world leader in serving science, we recognize the importance of considering how our products and services are used — or may be used — by our customers,” it said.

Human rights groups praised Thermo Fisher’s move. Still, they said, equipment and information flows into China should be better monitored, to make sure the authorities elsewhere don’t send them to Xinjiang.

“It’s an important step, and one hopes that they apply the language in their own statement to commercial activity across China, and that other companies are assessing their sales and operations, especially in Xinjiang,” said Sophie Richardson, the China director of Human Rights Watch.

American lawmakers and officials are taking a hard look at the situation in Xinjiang. The Trump administration is considering sanctions against Chinese officials and companies over China’s treatment of the Uighurs.

China’s tracking campaign unnerved people like Tahir Hamut. In May 2017, the police in the city of Urumqi in Xinjiang drew the 49-year-old Uighur’s blood, took his fingerprints, recorded his voice and took a scan of his face. He was called back a month later for what he was told was a free health check at a local clinic.

Mr. Hamut, a filmmaker who is now living in Virginia, said he saw between 20 to 40 Uighurs in line. He said it was absurd to think that such frightened people had consented to submit their DNA.

“No one in this situation, not under this much pressure and facing such personal danger, would agree to give their blood samples for research,” Mr. Hamut said. “It’s just inconceivable.”

By Paul Mozur

The Chinese government has drawn wide international condemnation for its harsh crackdown on ethnic Muslims in its western region, including holding as many as a million of them in detention camps.

Now, documents and interviews show that the authorities are also using a vast, secret system of advanced facial recognition technology to track and control the Uighurs, a largely Muslim minority. It is the first known example of a government intentionally using artificial intelligence for racial profiling, experts said.

The facial recognition technology, which is integrated into China’s rapidly expanding networks of surveillance cameras, looks exclusively for Uighurs based on their appearance and keeps records of their comings and goings for search and review. The practice makes China a pioneer in applying next-generation technology to watch its people, potentially ushering in a new era of automated racism.

The technology and its use to keep tabs on China’s 11 million Uighurs were described by five people with direct knowledge of the systems, who requested anonymity because they feared retribution. The New York Times also reviewed databases used by the police, government procurement documents and advertising materials distributed by the A.I. companies that make the systems.

Chinese authorities already maintain a vast surveillance net, including tracking people’s DNA, in the western region of Xinjiang, which many Uighurs call home. But the scope of the new systems, previously unreported, extends that monitoring into many other corners of the country.

The police are now using facial recognition technology to target Uighurs in wealthy eastern cities like Hangzhou and Wenzhou and across the coastal province of Fujian, said two of the people. Law enforcement in the central Chinese city of Sanmenxia, along the Yellow River, ran a system that over the course of a month this year screened whether residents were Uighurs 500,000 times.

Police documents show demand for such capabilities is spreading. Almost two dozen police departments in 16 different provinces and regions across China sought such technology beginning in 2018, according to procurement documents. Law enforcement from the central province of Shaanxi, for example, aimed to acquire a smart camera system last year that “should support facial recognition to identify Uighur/non-Uighur attributes.”

Some police departments and technology companies described the practice as “minority identification,” though three of the people said that phrase was a euphemism for a tool that sought to identify Uighurs exclusively. Uighurs often look distinct from China’s majority Han population, more closely resembling people from Central Asia. Such differences make it easier for software to single them out.

For decades, democracies have had a near monopoly on cutting-edge technology. Today, a new generation of start-ups catering to Beijing’s authoritarian needs are beginning to set the tone for emerging technologies like artificial intelligence. Similar tools could automate biases based on skin color and ethnicity elsewhere.

“Take the most risky application of this technology, and chances are good someone is going to try it,” said Clare Garvie, an associate at the Center on Privacy and Technology at Georgetown Law. “If you make a technology that can classify people by an ethnicity, someone will use it to repress that ethnicity.”

From a technology standpoint, using algorithms to label people based on race or ethnicity has become relatively easy. Companies like I.B.M. advertise software that can sort people into broad groups.

But China has broken new ground by identifying one ethnic group for law enforcement purposes. One Chinese start-up, CloudWalk, outlined a sample experience in marketing its own surveillance systems. The technology, it said, could recognize “sensitive groups of people.”

“If originally one Uighur lives in a neighborhood, and within 20 days six Uighurs appear,” it said on its website, “it immediately sends alarms” to law enforcement.

In practice, the systems are imperfect, two of the people said. Often, their accuracy depends on environmental factors like lighting and the positioning of cameras.

In the United States and Europe, the debate in the artificial intelligence community has focused on the unconscious biases of those designing the technology. Recent tests showed facial recognition systems made by companies like I.B.M. and Amazon were less accurate at identifying the features of darker-skinned people.

China’s efforts raise starker issues. While facial recognition technology uses aspects like skin tone and face shapes to sort images in photos or videos, it must be told by humans to categorize people based on social definitions of race or ethnicity. Chinese police, with the help of the start-ups, have done that.

“It’s something that seems shocking coming from the U.S., where there is most likely racism built into our algorithmic decision making, but not in an overt way like this,” said Jennifer Lynch, surveillance litigation director at the Electronic Frontier Foundation. “There’s not a system designed to identify someone as African-American, for example.”

The Chinese A.I. companies behind the software include Yitu, Megvii, SenseTime, and CloudWalk, which are each valued at more than $1 billion. Another company, Hikvision, that sells cameras and software to process the images, offered a minority recognition function, but began phasing it out in 2018, according to one of the people.

The companies’ valuations soared in 2018 as China’s Ministry of Public Security, its top police agency, set aside billions of dollars under two government plans, called Skynet and Sharp Eyes, to computerize surveillance, policing and intelligence collection.

In a statement, a SenseTime spokeswoman said she checked with “relevant teams,” who were not aware its technology was being used to profile. Megvii said in a statement it was focused on “commercial not political solutions,” adding, “we are concerned about the well-being and safety of individual citizens, not about monitoring groups.” CloudWalk and Yitu did not respond to requests for comment.

China’s Ministry of Public Security did not respond to a faxed request for comment.

Selling products with names like Fire Eye, Sky Eye and Dragonfly Eye, the start-ups promise to use A.I. to analyze footage from China’s surveillance cameras. The technology is not mature — in 2017 Yitu promoted a one-in-three success rate when the police responded to its alarms at a train station — and many of China’s cameras are not powerful enough for facial recognition software to work effectively.

Yet they help advance China’s architecture for social control. To make the algorithms work, the police have put together face-image databases for people with criminal records, mental illnesses, records of drug use, and those who petitioned the government over grievances, according to two of the people and procurement documents. A national database of criminals at large includes about 300,000 faces, while a list of people with a history of drug use in the city of Wenzhou totals 8,000 faces, they said.

Using a process called machine learning, engineers feed data to artificial intelligence systems to train them to recognize patterns or traits. In the case of the profiling, they would provide thousands of labeled images of both Uighurs and non-Uighurs. That would help generate a function to distinguish the ethnic group.

The A.I. companies have taken money from major investors. Fidelity International and Qualcomm Ventures were a part of a consortium that invested $620 million in SenseTime. Sequoia invested in Yitu. Megvii is backed by Sinovation Ventures, the fund of the well-known Chinese tech investor Kai-Fu Lee.

A Sinovation spokeswoman said the fund had recently sold a part of its stake in Megvii and relinquished its seat on the board. Fidelity declined to comment. Sequoia and Qualcomm did not respond to emailed requests for comment.

Mr. Lee, a booster of Chinese A.I., has argued that China has an advantage in developing A.I. because its leaders are less fussed by “legal intricacies” or “moral consensus.”

“We are not passive spectators in the story of A.I. — we are the authors of it,” Mr. Lee wrote last year. “That means the values underpinning our visions of an A.I. future could well become self-fulfilling prophecies.” He declined to comment on his fund’s investment in Megvii or its practices.

Ethnic profiling within China’s tech industry isn’t a secret, the people said. It has become so common that one of the people likened it to the short-range wireless technology Bluetooth. Employees at Megvii were warned about the sensitivity of discussing ethnic targeting publicly, another person said.

China has devoted major resources toward tracking Uighurs, citing ethnic violence in Xinjiang and Uighur terrorist attacks elsewhere. Beijing has thrown hundreds of thousands of Uighurs and others in Xinjiang into re-education camps.

The software extends the state’s ability to label Uighurs to the rest of the country. One national database stores the faces of all Uighurs who leave Xinjiang, according to two of the people.

Government procurement documents from the past two years also show demand has spread. In the city of Yongzhou in southern Hunan Province, law enforcement officials sought software to “characterize and search whether or not someone is a Uighur,” according to one document.

In two counties in Guizhou Province, the police listed a need for Uighur classification. One asked for the ability to recognize Uighurs based on identification photos at better than 97 percent accuracy. In the central megacity of Chongqing and the region of Tibet, the police put out tenders for similar software. And a procurement document for Hebei Province described how the police should be notified when multiple Uighurs booked the same flight on the same day.

A study in 2018 by the authorities described a use for other types of databases. Co-written by a Shanghai police official, the paper said facial recognition systems installed near schools could screen for people included in databases of the mentally ill or crime suspects.

One database generated by Yitu software and reviewed by The Times showed how the police in the city of Sanmenxia used software running on cameras to attempt to identify residents more than 500,000 times over about a month beginning in mid-February.

Included in the code alongside tags like “rec_gender” and “rec_sunglasses” was “rec_uygur,” which returned a 1 if the software believed it had found a Uighur. Within the half million identifications the cameras attempted to record, the software guessed it saw Uighurs 2,834 times. Images stored alongside the entry would allow the police to double check.

Yitu and its rivals have ambitions to expand overseas. Such a push could easily put ethnic profiling software in the hands of other governments, said Jonathan Frankle, an A.I. researcher at the Massachusetts Institute of Technology.

“I don’t think it’s overblown to treat this as an existential threat to democracy,” Mr. Frankle said. “Once a country adopts a model in this heavy authoritarian mode, it’s using data to enforce thought and rules in a much more deep-seated fashion than might have been achievable 70 years ago in the Soviet Union. To that extent, this is an urgent crisis we are slowly sleepwalking our way into.”

By Sui-Lee Wee and Paul Mozur

TUMXUK, China — In a dusty city in the Xinjiang region on China’s western frontier, the authorities are testing the rules of science.

With a million or more ethnic Uighurs and others from predominantly Muslim minority groups swept up in detentions across Xinjiang, officials in Tumxuk have gathered blood samples from hundreds of Uighurs — part of a mass DNA collection effort dogged by questions about consent and how the data will be used.

In Tumxuk, at least, there is a partial answer: Chinese scientists are trying to find a way to use a DNA sample to create an image of a person’s face.

The technology, which is also being developed in the United States and elsewhere, is in the early stages of development and can produce rough pictures good enough only to narrow a manhunt or perhaps eliminate suspects. But given the crackdown in Xinjiang, experts on ethics in science worry that China is building a tool that could be used to justify and intensify racial profiling and other state discrimination against Uighurs.

In the long term, experts say, it may even be possible for the Communist government to feed images produced from a DNA sample into the mass surveillance and facial recognition systems that it is building, tightening its grip on society by improving its ability to track dissidents and protesters as well as criminals.

Some of this research is taking place in labs run by China’s Ministry of Public Security, and at least two Chinese scientists working with the ministry on the technology have received funding from respected institutions in Europe. International scientific journals have published their findings without examining the origin of the DNA used in the studies or vetting the ethical questions raised by collecting such samples in Xinjiang.

In papers, the Chinese scientists said they followed norms set by international associations of scientists, which would require that the men in Tumxuk (pronounced TUM-shook) gave their blood willingly. But in Xinjiang, many people have no choice. The government collects samples under the veneer of a mandatory health checkup program, according to Uighurs who have fled the country. Those placed in internment camps — two of which are in Tumxuk — also have little choice.

The police prevented reporters from The New York Times from interviewing Tumxuk residents, making verifying consent impossible. Many residents had vanished in any case. On the road to one of the internment camps, an entire neighborhood had been bulldozed into rubble.

Growing numbers of scientists and human rights activists say the Chinese government is exploiting the openness of the international scientific community to harness research into the human genome for questionable purposes.

Already, China is exploring using facial recognition technology to sort people by ethnicity. It is also researching how to use DNA to tell if a person is a Uighur. Research on the genetics behind the faces of Tumxuk’s men could help bridge the two.

The Chinese government is building “essentially technologies used for hunting people,” said Mark Munsterhjelm, an assistant professor at the University of Windsor in Ontario who tracks Chinese interest in the technology.

In the world of science, Dr. Munsterhjelm said, “there’s a kind of culture of complacency that has now given way to complicity.”

Mapping China’s Faces

Sketching someone’s face based solely on a DNA sample sounds like science fiction. It isn’t.

The process is called DNA phenotyping. Scientists use it to analyze genes for traits like skin color, eye color and ancestry. A handful of companies and scientists are trying to perfect the science to create facial images sharp and accurate enough to identify criminals and victims.

The Maryland police used it last year to identify a murder victim. In 2015, the police in North Carolina arrested a man on two counts of murder after crime-scene DNA indicated the killer had fair skin, brown or hazel eyes, dark hair, and little evidence of freckling. The man pleaded guilty.

Despite such examples, experts widely question phenotyping’s effectiveness. Currently, it often produces facial images that are too smooth or indistinct to look like the face being replicated. DNA cannot indicate other factors that determine how people look, such as age or weight. DNA can reveal gender and ancestry, but the technology can be hit or miss when it comes to generating an image as specific as a face.

Phenotyping also raises ethical issues, said Pilar Ossorio, a professor of law and bioethics at the University of Wisconsin-Madison. The police could use it to round up large numbers of people who resemble a suspect, or use it to target ethnic groups. And the technology raises fundamental issues of consent from those who never wanted to be in a database to begin with.

“What the Chinese government is doing should be a warning to everybody who kind of goes along happily thinking, ‘How could anyone be worried about these technologies?’” Dr. Ossorio said.

With the ability to reconstruct faces, the Chinese police would have yet another genetic tool for social control. The authorities have already gathered millions of DNA samples in Xinjiang. They have also collected data from the hundreds of thousands of Uighurs and members of other minority groups locked up in detention camps in Xinjiang as part of a campaign to stop terrorism. Chinese officials have depicted the camps as benign facilities that offer vocational training, though documents describe prisonlike conditions, while testimonies from many who have been inside cite overcrowding and torture.

Even beyond the Uighurs, China has the world’s largest DNA database, with more than 80 million profiles as of July, according to Chinese news reports.

“If I were to find DNA at a crime scene, the first thing I would do is to find a match in the 80 million data set,” said Peter Claes, an imaging specialist at the Catholic University of Leuven in Belgium, who has studied DNA-based facial reconstruction for a decade. “But what do you do if you don’t find a match?”

Though the technology is far from accurate, he said, “DNA phenotyping can bring a solution.”

The Scientific Community

To unlock the genetic mysteries behind the human face, the police in China turned to Chinese scientists with connections to leading institutions in Europe.

One of them was Tang Kun, a specialist in human genetic diversity at the Shanghai-based Partner Institute for Computational Biology, which was founded in part by the Max Planck Society, a top research group in Germany.

The German organization also provided $22,000 a year in funding to Dr. Tang because he conducted research at an institute affiliated with it, said Christina Beck, a spokeswoman for the Max Planck Society. Dr. Tang said the grant had run out before he began working with the police, according to Dr. Beck.

Another expert involved in the research was Liu Fan, a professor at the Beijing Institute of Genomics who is also an adjunct assistant professor at Erasmus University Medical Center in the Netherlands.

Both were named as authors of a 2018 study on Uighur faces in the journal Hereditas (Beijing), published by the government-backed Chinese Academy of Sciences. They were also listed as authors of a study examining DNA samples taken last year from 612 Uighurs in Tumxuk that appeared in April in Human Genetics, a journal published by Springer Nature, which also publishes the influential journal Nature.

Both papers named numerous other authors, including Li Caixia, chief forensic scientist at the Ministry of Public Security.

In an interview, Dr. Tang said he did not know why he was named as an author of the April paper, though he said it might have been because his graduate students worked on it. He said he had ended his affiliation with the Chinese police in 2017 because he felt their biological samples and research were subpar.

“To be frank, you overestimate how genius the Chinese police is,” said Dr. Tang, who had recently shut down a business focused on DNA testing and ancestry.

Like other geneticists, Dr. Tang has long been fascinated by Uighurs because their mix of European and East Asian features can help scientists identify genetic variants associated with physical traits. In his earlier studies, he said, he collected blood samples himself from willing subjects.

Dr. Tang said the police approached him in 2016, offering access to DNA samples and funding. At the time, he was a professor at the Partner Institute for Computational Biology, which is run by the Chinese Academy of Sciences but was founded in 2005 in part with funding from the Max Planck Society and still receives some grants and recommendations for researchers from the German group.

Dr. Beck, the Max Planck spokeswoman, said Dr. Tang had told the organization that he began working with the police in 2017, after it had stopped funding his research a year earlier.

But an employment ad on a government website suggests the relationship began earlier. The Ministry of Public Security placed the ad in 2016 seeking a researcher to help explore the “DNA of physical appearance traits.” It said the person would report to Dr. Tang and to Dr. Li, the ministry’s chief forensic scientist.

Dr. Tang did not respond to additional requests for comment. The Max Planck Society said Dr. Tang had not reported his work with the police as required while holding a position at the Partner Institute, which he did not leave until last year.

The Max Planck Society “takes this issue very seriously” and will ask its ethics council to review the matter, Dr. Beck said.

It is not clear when Dr. Liu, the assistant professor at Erasmus University Medical Center, began working with the Chinese police. Dr. Liu says in his online résumé that he is a visiting professor at the Ministry of Public Security at a lab for “on-site traceability technology.”

In 2015, while holding a position with Erasmus, he also took a post at the Beijing Institute of Genomics. Two months later, the Beijing institute signed an agreement with the Chinese police to establish an innovation center to study cutting-edge technologies “urgently needed by the public security forces,” according to the institute’s website.

Dr. Liu did not respond to requests for comment.

Erasmus said that Dr. Liu remained employed by the university as a part-time researcher and that his position in China was “totally independent” of the one in the Netherlands. It added that Dr. Liu had not received any funding from the university for the research papers, though he listed his affiliation with Erasmus on the studies. Erasmus made inquiries about his research and determined there was no need for further action, according to a spokeswoman.

Erasmus added that it could not be held responsible “for any research that has not taken place under the auspices of Erasmus” by Dr. Liu, even though it continued to employ him.

Still, Dr. Liu’s work suggests that sources of funding could be mingled.

In September, he was one of seven authors of a paper on height in Europeans published in the journal Forensic Science International. The paper said it was backed by a grant from the European Union — and by a grant from China’s Ministry of Public Security.

The Question of Consent

Dr. Tang said he was unaware of the origins of the DNA samples examined in the two papers, the 2018 paper in Hereditas (Beijing) and the Human Genetics paper published in April. The publishers of the papers said they were unaware, too.

Hereditas (Beijing) did not respond to a request for comment. Human Genetics said it had to trust scientists who said they had received informed consent from donors. Local ethics committees are generally responsible for verifying that the rules were followed, it said.

Springer Nature said on Monday that it had strengthened its guidelines on papers involving vulnerable groups of people and that it would add notes of concern to previously published papers.

In the papers, the authors said their methods had been approved by the ethics committee of the Institute of Forensic Science of China. That organization is part of the Ministry of Public Security, China’s police.

With 161,000 residents, most of them Uighurs, the agricultural settlement of Tumxuk is governed by the powerful Xinjiang Production and Construction Corps, a quasi-military organization formed by decommissioned soldiers sent to Xinjiang in the 1950s to develop the region.

The state news media described Tumxuk, which is dotted with police checkpoints, as one of the “gateways and major battlefields for Xinjiang’s security work.”

In January 2018, the town got a high-tech addition: a forensic DNA lab run by the Institute of Forensic Science of China, the same police research group responsible for the work on DNA phenotyping.

Procurement documents showed the lab relied on software systems made by Thermo Fisher Scientific, a Massachusetts company, to work with genetic sequencers that analyze DNA fragments. Thermo Fisher announced in February that it would suspend sales to the region, saying in a statement that it had decided to do so after undertaking “fact-specific assessments.”

For the Human Genetics study, samples were processed by a higher-end sequencer made by an American firm, Illumina, according to the authors. It is not clear who owned the sequencer. Illumina did not respond to requests for comment.

The police sought to prevent two Times reporters from conducting interviews in Tumxuk, stopping them upon arrival at the airport for interrogation. Government minders then tailed the reporters and later forced them to delete all photos, audio and video recordings taken on their phones in Tumxuk.

Uighurs and human rights groups have said the authorities collected DNA samples, images of irises and other personal data during mandatory health checks.

In an interview, Zhou Fang, the head of the health commission in Tumxuk, said residents voluntarily accepted free health checks under a public health program known as Physicals for All and denied that DNA samples were collected.

“I’ve never heard of such a thing,” he said.

The questions angered Zhao Hai, the deputy head of Tumxuk’s foreign affairs office. He called a Times reporter “shameless” for asking a question linking the health checks with the collection of DNA samples.

“Do you think America has the ability to do these free health checks?” he asked. “Only the Communist Party can do that!”

A secret document reflects leaders’ struggle to manage Xinjiang sites swelling with Muslim detainees.

By Austin Ramzy and Chris Buckley

HONG KONG — As the government accelerated mass detentions of Muslim minorities in northwest China, a senior official issued a secret directive giving detailed orders for how the rapidly expanding indoctrination camps holding them should be managed.

Guards should impose pervasive, round-the-clock video surveillance to prevent escapes. Inmates were to be kept isolated from the outside world and held to a strict scoring system that could determine when they might be released. And the facilities were to be shrouded in secrecy, with even employees banned from bringing in mobile phones.

“It is necessary,” the directive from two years ago said, “to strengthen the staff’s awareness of staying secret, serious political discipline and secrecy discipline.”

Now that secrecy has been shattered with the publication of the directive itself. It is one of six internal documents obtained by the International Consortium of Investigative Journalists that shed new light on China’s crackdown in the Xinjiang region, where a million or more ethnic Uighurs, Kazakhs and others have been detained in the past three years.

The disclosure of the 24 pages of documents amounts to a second significant leak from inside China’s ruling Communist Party related to the crackdown. A member of the Chinese political establishment shared a different, 403-page set of internal papers with The New York Times earlier this year, expressing hope that it would make it more difficult for party leaders, including President Xi Jinping, to escape culpability for the mass detentions.

While the source of the new documents is unknown — they were provided by Uighur overseas networks — their disclosure may amount to another sign of dissent in the party over the crackdown.

The International Consortium of Investigative Journalists, an independent nonprofit based in Washington, led the inquiry into the documents, bringing together more than 75 journalists from the consortium and 17 partner organizations, including The Times, in 14 countries. Outside experts also reviewed the papers and concluded they were authentic.

“In terms of documentary evidence, we have reached a next level of disclosure,” said Adrian Zenz, a researcher who has studied the camps and a senior fellow in China studies at the Victims of Communism Memorial Foundation, a human rights group in Washington. “The evidence we have now is very comprehensive, very complete. It’s kind of game over for Beijing in terms of the cover-up, the denials and the half-truths.”

The most significant of the new documents is the secret directive on how to manage the camps, which is the only document in both sets of leaked papers to describe the inner workings of these facilities. The nine-page order was issued in November 2017 by the Communist Party committee in Xinjiang that oversees legal affairs

The papers also include four “daily bulletins” from another regional party committee that provide information about those that have been targeted for investigation and detention in camps and a court judgment sentencing a Uighur resident to 10 years in prison on charges of inciting ethnic hatred and discrimination, a vaguely defined crime.

‘Prevent escapes’

Beijing has rejected criticism of the camps and described them as job-training centers that use humane methods to fight the spread of Islamic extremism. Internally, the government often uses language consistent with that position. The leaked directive, for example, refers to the camps as “vocational skills education and training centers” and the detainees as “students.”

But it also lays bare the punitive underpinnings of these facilities, and some of its language on guarding against escapes and other incidents is identical to that used in guidelines for prisons and other detention sites.

The orders called on guards to strictly control and monitor the activities of students. “Prevent escapes while they are at class, dining, using the toilet, washing, receiving medical care or meeting with family.”

Other instructions call for erecting guardhouses and internal partitions inside the camps to prevent inmates from moving around freely; rigorously checking any people, vehicles or goods entering, and recruiting informants to spy on other detainees.

“Evaluate and resolve students’ ideological problems and abnormal emotions at all times,” the directive said.

The document included orders for “full video surveillance coverage of dormitories and classrooms free of blind spots,” and prohibited detainees from having contact with the outside world, except in strictly monitored interactions.

The government says these sites help prevent Uighurs and other Muslims from being drawn to religious extremism by teaching them the Chinese language, job skills and how to be law-abiding citizens. In response to the earlier leak of documents, the government argued that its methods have effectively stifled extremist violence in Xinjiang.

Former detainees, though, have described the classes as numbing, harsh and ultimately futile attempts at brainwashing. And residents have been sent to internment camps for behavior that would be commonplace elsewhere: traveling abroad, showing signs of religious devotion praying regularly or growing a long beard, or installing certain cellphone apps, such as encrypted messaging tools.

Mr. Zenz, the scholar who reviewed the documents, said he also obtained a cache of more than 25,000 files from government departments that provides new detail on the scale of the detentions and their impact on families.

In six villages in Yarkand, a county in southwestern Xinjiang where nearly all the residents are Uighur, he found that about one in six rural adult residents were interned or in prison. In two villages in that county, nearly 60 percent of households had at least one person in custody.

The detainees in Xinjiang are mostly working-age men, he wrote in a new paper, and that has led to hardships for families. In one case Mr. Zenz documented, five children were effectively orphaned after their father was imprisoned and their mother put in an indoctrination camp.

One of the leaked daily bulletins orders an investigation of people from Xinjiang who have obtained foreign citizenship or applied for visas or other documents at Chinese embassies abroad.

Another describes how 15,683 “suspicious persons” were sent to centers in southern Xinjiang on the week of June 19, 2017. The government has repeatedly refused to say how many people are being held in these camps.

Other bulletins reveal how the authorities settled on targets for detention by using databases that collect and collate information on Xinjiang residents, especially Uighurs and other Muslim minorities.

The daily bulletins and the document on camp operations were signed by Zhu Hailun, who was then the top security official in Xinjiang. He was assigned to another position in the regional legislature early this year.

Mr. Zhu, 61, appears to have been a key enforcer of the internment campaign, turning the orders of the regional party secretary, Chen Quanguo, into detailed plans. A party official who spent his career in Xinjiang, Mr. Zhu had previously served as the head of Xinjiang’s capital, Urumqi, succeeding an official who was fired in 2009 after bloody ethnic riots killed nearly 200 people, most of them Han Chinese.

Like many in his generation, Mr. Zhu was no stranger to the idea that minds can be reprogrammed through intense indoctrination and propaganda: He grew up in Mao’s era, when such techniques were widespread. In an official biography, Mr. Zhu described the two years he spent as a teenager working in a rural commune as a period of “re-education.”

Over 40 years later, Mr. Zhu was uncompromising as Mr. Chen’s right-hand man for security. An internal document from 2017 signed by Mr. Zhu that was among the papers leaked to The Times attributed attacks in London and Manchester in part to putting “human rights above security.”

‘Promote repentance’

The directive on camp operations instructed officials to keep extensive records on detainees, and described a scoring system that measured how they behaved to determine their fate.

Inmates should be assigned to one of three zones based on how dangerous they are judged to be — general management, strict, and very strict, the document said. But detainees could be moved between the grades of control depending on their scores.

“Break down scores and manage and individually assess the students’ ideological transformation, study and training, and compliance with discipline,” the document said.

Officials were told to assign inmates to fixed positions in dormitories, classes, lineups and workshops, and to control every detail of life inside the camps, at every moment of the day, including wake-up, meals, studies and showers.

Detainees must meet “disciplinary demands” or face punishment, the directive added.

“Strengthen the management of the students’ hygiene,” it said. “Ensure that they get timely haircuts and shave, change and wash their clothes. Arrange for them to have baths once or twice a week, so that they develop good habits.”

The demands listed in the directive echoed the accounts of former detainees like Orynbek Koksebek, an ethnic Kazakh man who spent four months in an indoctrination camp in Xinjiang after being detained by the Chinese authorities in December 2017.

“There was military discipline in everything we did, how you walk, stand up straight. If you didn’t, they would slap you,” he said in an interview in the Kazakh city of Almaty earlier this year.

A key disclosure in the leaked directive is an official description of the conditions that detainees must meet to be released from the camps. Aside from achieving a good score in the point system, the document said, inmates must be categorized at the lowest threat level and have served a minimum term of one year — though interviews with former detainees indicate that camps sometimes release people sooner.

The directive also emphasized the importance of showing remorse. Discussions with detainees should “promote the repentance and confession of the students for them to understand deeply the illegal, criminal and dangerous nature of their past behavior,” it said.

A different document, among the set shared with The Times earlier this year, described how family members outside the camps are told that their behavior can also affect when a detainee is released — a implied threat aimed at silencing complaints.

Former detainees said the criteria for release seemed arbitrary, and there was little clarity on when or why people could leave.

“You enter the camp with 1,000 points. You can’t gain points. You can only lose them if you yawn or smile,” recalled Rahima Senbai, who was held in a camp in October 2017 and only allowed to return to her home in Kazakhstan a year later. “If you ever went under 500 points, you’d have to stay for another year.”

Zharqynbek Otan, who was held in a camp for seven months after his arrest in January 2017 and has since fled China, said the goal of the detention was to impose loyalty to the Chinese state.

“The main purpose is to brainwash you,” he said, “so you forget your roots and everything about Islam and ethnic identity.”