PUYANG, China—One night this September, construction supervisor Chen Shouli fired off a joke in a chat group.

“Haha,” he typed on his black iPhone 7, followed by an off-color wisecrack about a rumored love triangle involving a celebrity and one of China’s most senior government officials.

Four days later, he says, the police telephoned, ordering him in for questioning.

“I thought, I haven’t done anything wrong, have I? I’m law-abiding,” recalls Mr. Chen, a wiry 41-year-old. “So I went in. Once I arrived, they wouldn’t let me leave.”

Mr. Chen was locked in a cell for five days, he says. According to the police report, his comment on the WeChat messaging app was deemed “picking quarrels and provoking trouble,” a broad offense that encompasses gang fighting and destruction of public property and is punishable by detention without trial.


In China’s swiftly evolving new world of state surveillance, there are fewer and fewer private spaces. Authorities who once had to use informants to find out what people said in private now rely on a vast web of new technology. They can identify citizens as they walk down the street, monitor their online behavior and snoop on cellphone messaging apps to identify suspected malcontents.

Years ago, in the Mao Zedong era, people were sent to prison, labor camps and death for opinions expressed in private. In the decades since China launched economic reforms after Mao’s death, prosperity and social mobility created room for more personal freedom and expression. Now China appears to be reverting to old form, empowered by new digital surveillance tools.

That means ordinary people such as Mr. Chen increasingly find themselves investigated and punished for imprudent comments they thought were private. It is now easy for a regular citizen to step over the brink, with a stray comment to family or friends screenshotted into evidence, without the need for an informant.

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Mr. Chen is now marked as a troublemaker by local officials and police, who have warned him to mind what he does. Some friends, he says, now keep their distance.


One recent afternoon, he argued with his wife about the detention in their cramped one-bedroom apartment on the edge of the small eastern city of Puyang.

“This incident is over,” she told him.

“You don’t understand,” he shot back. “It’s far, far from over.”

Police in Puyang didn’t respond to a request for comment, nor did Tencent Holdings Ltd., which owns WeChat.


In September, amid a drunken-driving clampdown in the city of Jieshou, auto mechanic Yang Qingsong used an expletive in a WeChat post to question the intelligence of police for doing checks in the rain. Police detained Mr. Yang for five days, saying his post to a group with 241 people “created negative social effects,” according to an account of the incident the police posted on Weibo, China’s equivalent of Twitter.

“Had I known it would be so serious, I wouldn’t have sent it,” says Mr. Yang, 24, who set up his own auto-repair shop last year.

Photo: Eva Dou/The Wall Street Journal

“ We already can’t speak on blogs. Can we draw a bottom line somewhere? Can we speak a little bit in our living rooms? ” — Zhu Shengwu, lawyer

Unlike postings to a blog or Twitter-like microblog, which are generally public platforms, chats on messaging apps such as WeChat are more private, limited to members accepted into a group. Larger ones have to meet stricter registration conditions imposed by the company, and WeChat caps groups at 500.

Zhu Shengwu was an intellectual-property lawyer in cases involving technology firms such as search engine Baidu Inc. before taking on a free-speech case this year. He says that monitoring closed chats is akin to eavesdropping in someone’s home.


“We already can’t speak on blogs,” says Mr. Zhu. “Can we draw a bottom line somewhere? Can we speak a little bit in our living rooms?”

Chinese dissidents and foreign academics had predicted that information dispersed over the internet and through mobile communications would loosen the government’s grip. But Chinese authorities have surmounted, one by one, the technological difficulties of monitoring text messages, emails, blogs and chat sites. Messaging apps, and WeChat in particular, are its latest challenge.

WeChat is China’s most popular social-media platform, by far, with users sending 38 billion messages each day. It isn’t clear how many private WeChat messages get deleted by Tencent because of government censorship requirements. WeChat also has a function to post publicly. Citizen Lab, an internet research center at the University of Toronto, examined 36,000 public posts in 2015 and found 4% were censored.

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Software employed by WeChat appears to automatically scrub posts containing words on a blacklist, which is continually amended by human censors, according to Citizen Lab. The technology has now advanced to identify images deemed sensitive, which are then removed during transmission without the sender being alerted to the disruption.

The government has introduced rules and judicial interpretations making it a crime punishable by up to three years of prison time to spread what officials deem “false rumors.” A new rule this fall made any individual who forms a private chat group legally responsible for comments posted there by others.

Most people caught posting objectionable content just see it deleted and sometimes receive a warning. Heavier punishment usually is reserved for people already targeted by authorities for being known political critics or social activists, or for having a record of past offenses.

Wang Jiangfeng, pictured in a undated photo supplied by his wife, is serving a 22-month prison sentence for disparaging government leaders in a WeChat chat group. Photo: Sun Wenjuan

Wang Jiangfeng lost his job at a local agricultural cooperative in the eastern city of Zhaoyuan more than a decade ago, after he was accused of embezzling a payment from an apple-juice factory, says his wife, Sun Wenjuan. Mr. Wang denied the accusation and called his dismissal unjust. He spent years petitioning government offices from Zhaoyuan to Beijing for redress, landing him repeatedly in detention and alienating local officials in the process, she says.

After he called President Xi Jinping a “baozi”—a steamed dumpling—in one WeChat post, and Chairman Mao a “bandit” in another, Mr. Wang was arrested, court records say. A local court in April sentenced him to two years in prison, a term that was reduced to 22 months after a retrial last month.

The prison sentence “was clearly motivated by retaliation,” Ms. Sun says. “The local officials had their eyes on him.”

Mr. Wang sobbed after the initial verdict, shocked that WeChat comments could draw such a harsh penalty, says Mr. Zhu, his lawyer. Shortly after the first sentencing, Mr. Zhu began criticizing the justice system in posts on the Weibo microblog. The provincial justice department ruled that several posts endangered national security, disbarring him as punishment.

Photo: Josh Chin/The Wall Street Journal

“ The local officials had their eyes on him. ” — Sun Wenjuan, wife of Wang Jiangfeng

The Zhaoyuan People’s Court, which sentenced Mr. Wang, didn’t respond to a request for comment, nor did the Shandong provincial justice department, which disbarred Mr. Zhu.

Stern treatment is now being meted out to ordinary people without records of prior offenses, according to Mr. Zhu and other lawyers.

“In the past, there were these kinds of cases at times,” says Mo Shaoping, a prominent human-rights lawyer. “But it wasn’t like now, where they are seizing people so blatantly and confidently.”

China’s Public Security Ministry, Justice Ministry and Cyberspace Administration didn’t respond to requests for comment.

Mr. Chen, the construction supervisor in Puyang, says that while he wasn’t an activist, he was interested in politics and social issues—frequent topics of the chat group “Drips of Water Wear Through Stone.” Some talk in the group touched on Guo Wengui, a self-exiled billionaire living in New York who frequently used Twitter and other social media outside China to accuse senior Chinese officials of misconduct. Mr. Guo says he wants to expose what he calls China’s “kleptocrats” and bring rule of law to the country.

Censors and police wanted to squelch comments from Mr. Guo that leaked through the firewall and to prevent any disruption to a critical Communist Party congress in October to reappoint Mr. Xi as China’s top leader.

Photo: Eva Dou/The Wall Street Journal

“ In the past, there were these kinds of cases at times. But it wasn’t like now, where they are seizing people so blatantly and confidently. ” — Mo Shaoping, human-rights lawyer

Politically minded Chinese complained of a tide of chat-group shutdowns. Mr. Mo, the rights lawyer, said his WeChat account was suspended in October, after he forwarded a news report about Mr. Guo to a few friends in one-on-one chats. Though he has defended many dissidents, including the writer and eventual Nobel Peace Prize winner Liu Xiaobo, he says he never before lost his WeChat account.

Mr. Chen typed his joke at 10:45 p.m. on Sept. 15, starting with “Haha.” Alluding to an allegation made by Mr. Guo, he wrote that if the rumors are true about an affair between a TV singing-competition star and someone surnamed Meng, then that would make the singer’s husband a cuckold.

Mr. Chen named the singer and her husband, but only used the official’s surname. For politically minded Chinese, the “Meng” clearly referred to Meng Jianzhu, who oversaw the nation’s law-enforcement system. Mr. Meng didn’t respond to a request for comment submitted for him through China’s Foreign Ministry.

Mr. Chen doesn’t know how his comment got flagged. While police often monitor the social-media accounts of known social activists, Mr. Chen had no previous run-ins with authorities, he says. He thinks the official’s name he mentioned may have been on a watch list, or perhaps someone among the chat group’s 453 members tattled.

Mr. Chen, who stands shy of 5 feet tall, recalls growing up poor, feeling hunger pangs and scrounging for food. Donggancheng village, outside Puyang, had no electricity, and the family home was made of blocks of mud mixed with wheat stalks. His father, one of only three college graduates in the village of 3,000, was the local doctor.

Like many of his neighbors, Mr. Chen now has a car and a smartphone. He and his wife live in a two-story apartment building near where Donggancheng village once stood. Together they run a small shop selling smartphones, while he works construction jobs and she sells insurance.

After first his father and then his mother were diagnosed with cancer, the family’s savings were drained paying medical bills. His unhappiness with the medical system drove him to seek information in WeChat groups, he says. He wondered whether the factory pollution ravaging the surrounding countryside caused his parents’ cancers. He says he began calling the local environment bureau to report violations.

As he read and chatted more on his phone, he learned that some major nations had free universal health care and that, also unlike many other world powers, China had autocratic rule.

“Gradually I became aware of it all,” says Mr. Chen. “My thinking didn’t develop in a day or two. It slowly, slowly accumulated.”

When Mr. Chen reported to the local police station on Sept. 19, he says, officers made it clear they had seen his WeChat post. They asked him to confirm that his WeChat name was “The Flash of a Thought.” Then they asked him to pull up the chat group on his phone.

Mr. Chen says officers grilled him for hours on everything from whether he has religious beliefs to what he thinks about China’s leaders and blacklisted dissidents. He says he wasn’t mistreated.

Security cameras were installed near Chen Shouli’s apartment in Puyang. Photo: Eva Dou/The Wall Street Journal

He and several cellmates took turns taking cold showers in the hot weather, then sat around on stools because lying down wasn’t allowed for most of the day, he says. At night, unable to sleep, he ruminated about his situation. His cellmates, he says, thought it hilarious that he was there for a WeChat comment.

After his release, Mr. Chen says, relatives, friends and officials all told him to learn his lesson and move on. Still, his detention nagged at him more than he anticipated. “I’ve lost some friends,” he says. “Some people now speak to me with reserve.”

Security cameras were installed outside his apartment building. Mr. Chen doesn’t believe they are there because of him.

He and some other villagers discussed his detention recently over a lunch of dumplings and fiery baijiu grain liquor. A neighbor said it was Mr. Chen’s own fault for writing the comment. “There are things you can say, and things you can’t say,” another neighbor piped in.

“If you were punished, you surely did something wrong,” said the ruddy-faced village chief, Yang Cunfu. “That online post had too big an impact on society.”

Mr. Chen responded that a post that starts with “haha” shouldn’t create such a stir: “I still don’t think I did anything wrong.”

—Josh Chin contributed to this article.