PHOTO ESSAY: Those caught in the dragnet of China's digital cage enabled by U.S. tech

CHANGZHOU, China — China runs the largest digital surveillance apparatus on earth. An Associated Press investigation has found that American tech companies to a large degree designed and built China’s surveillance state, playing a far greater role in enabling human rights abuses than previously known.

Many in China hardly notice the country’s millions of cameras. But for the tens of thousands under watch, it’s an invisible digital cage, tracking and restricting their movement.

Among them are the Yang family, living in rural eastern Jiangsu province. Caught in a land dispute, they’ve been trying to seek relief from local officials by appealing to China’s central government in Beijing. But this surveillance apparatus based on American technology monitors and predicts their every move, flagging them for detention every time they try to go to the Chinese capital.

Yang Guoliang lives alone, a virtual prisoner in his own house. His wife and younger daughter were arrested last year and now face trial for disrupting the work of the Chinese state — a crime carrying a sentence of up to a decade in prison.

“Every move in my own home is monitored,” Yang says, sitting behind black curtains that block him from the gaze of the cameras trained straight at his house. “Their surveillance makes me feel unsafe all the time, everywhere.”

His elder daughter, Yang Caiying, is advocating for their family from Japan, where she now lives.

“Because of this technology … we have no freedom at all,” Yang Caiying says. “Sooner or later, Americans and others, too, will lose their freedoms.”

Legal and tech experts say among the most egregious use of these technologies was during a brutal mass detention campaign in China’s far west Xinjiang region. Such technologies targeted, tracked and graded virtually the entire native Uyghur population to forcibly assimilate and subdue them.

Former Xinjiang government engineer Nureli Abliz saw firsthand how surveillance technology flagged thousands of people for detention, even when they had committed no crime.

For years, Abliz kept silent, worried about his family’s safety. But now that he’s in exile in Germany, Abliz is speaking up.

Abliz described how Xinjiang’s surveillance systems mine a vast array of information — texts, calls, payments, flights, video, DNA swabs, mail deliveries, the internet, even water and power use — to unearth individuals deemed suspicious and predict their movements. Such systems allowed Chinese police to preemptively detain people for crimes they have not even committed.

“They thought it better to grab thousands of innocents than let a single criminal slip free,” Abliz said.

The Xinjiang government says it uses surveillance technologies to “prevent and combat terrorist and criminal activity,” and that it does not target any particular ethnicity.