Policemen stand in formation as they guard on the bund where people were killed in a stampede incident during a new year's celebration, in Shanghai, on Jan. 3. Chinese state media and the public criticised the government and police on Friday for failing to prevent the stampede in Shanghai that killed 36 people and dented the city's image as modern China's global financial hub. (China Stringer Network/Reuters)

— Zhang Miao has now been in prison for almost four months.

She is a Chinese researcher for a German newspaper in China, and her arrest has sparked fear, outrage and some soul-searching among foreign news organizations in China about the role of their Chinese assistants.

Reporting from China has become increasingly difficult and harrowing in recent years for both Chinese and foreign media, with a sweeping crackdown on press freedom since China’s President Xi Jinping took power.

According to the New York-based Committee to Protect Journalists, China had more journalists in prison last year than any other country. Most were Chinese citizens.

For years, the most common threat to foreign news outlets has been expulsion. But increasingly, Chinese authorities are attacking news bureaus at their most vulnerable point: their dependence on Chinese citizens who translate and facilitate their coverage.

Security personnel order an accredited foreign journalist to stop filming in front of the entrance to Bobo Freedom Village where Chinese dissident Zeng Jinyan lives under unofficial house arrest on October 10, 2008 in Beijing. (FREDERIC J. BROWN/AFP/Getty Images)

Zhang Miao’s case — detailed for the first time by the German newspaper, Die Zeit, last week — shocked many because of how aggressively authorities have punished Zhang and threatened the German reporter she worked with.

“It’s a scary thing for all of us because it shows how serious and how far authorities will go if they want to create a case against you,” said a U.S. reporter, speaking anonymously to avoid drawing government scrutiny.

Working with news assistants, known as “fixers,” is a common practice around the world for foreign news bureaus. But unlike in most countries, researchers in China are strictly regulated by the government and subject to complicated rules that govern everything from their ability to meet interview subjects on their own to banning their names on story bylines.

Those rules forbid them from being hired outright by foreign news outlets and instead require them to be hired under contracts with China’s government — an arrangement designed to keep them under the authorities’ watch.

In the past year, news assistants have reported a sharp uptick in harassment. In a survey conducted last spring by the Foreign Correspondents Club of China, more than half the responding correspondents said their assistants had been harassed, up from 35 percent in 2013.

A few were detained overnight and pressured into spying on foreign journalists for the government. Others said their relatives have been threatened and pressured.

Often, there is an invitation to “drink tea” with the authorities — a euphemism for meetings in which the news assistants are questioned about their bureau’s reporting activities.

Zhang, 40, had worked for two years as a news assistant to Angela Köckritz, 37, a correspondent for the Hamburg-based Die Zeit weekly newspaper. When pro-democracy protests broke out in Hong Kong this fall, Zhang flew with Köckritz to cover them .

Zhang later returned to Beijing while Köckritz remained in Hong Kong. Shortly afterward, she was arrested by police at an artists’ colony on the outskirts of Beijing.

According to Köckritz, Zhang had felt inspired by the protests, and said so on Chinese social media posts. She was taken away with 11 others as they were on their way to a poetry reading in support of the protests.

In a phone interview, Köckritz said she met with Chinese authorities several times — and later with German embassy officials — to lobby for Zhang’s release.

The meetings grew increasingly acrimonious.

“It was scary,” Köckritz said. She detailed the experience in a 6,500-word piece in Die Zeit. “They play all these psychological games on you, and they spin everything to try to push you into losing control and saying or doing something irrational or stupid.”

During her last meeting with authorities, lasting 41/2 hours, they began suggesting that Köckritz was a foreign spy who went to Hong Kong to help organize the protests.

Worried for her safety, Köckritz left China the next day.

Zhang was not allowed to see a lawyer until Dec. 10, more than two months into her detention, in violation of Chinese law. The German newspaper said it held off at first on releasing details of Zhang’s arrest in case it might hurt diplomatic efforts to free her, but more than three months later there has been little movement.

Two weeks after fleeing, Köckritz returned to China for a short time to pack up her belongings and finish reporting for a book. She now lives in Berlin. Die Zeit and the German embassy said they are continuing to press for Zhang’s release.

When asked about Zhang’s detention in October, China’s foreign ministry said Zhang had not been registered with the government as a properly accredited assistant for Die Zeit. Some news outlets have opted against registering their assistants to avoid a $100-a-month “management fee” and other even higher costs charged by the government, and out of concern that doing so might attract increased government surveillance. But others believe that this exposes news assistants to greater risk and has no effect on already ubiquitous surveillance.

During her interrogations, authorities told Köckritz she had no legal authority to intercede for Zhang because she was not a registered as working for Die Zeit.

Some correspondents have questioned Köckritz for not registering Zhang and not steering her away from getting socially involved with activists. But they and human rights groups are quick to point out that neither activity — even if for some reason deemed illegal — justifies months of imprisonment.

In an e-mail, Moritz Mueller-Wirth, an editor at Die Zeit, said the decision to not register Zhang was made by the newspaper’s editorial board and was not for financial reasons. It was, he wrote, to shield her “from the supervision of the state security. When Zhang Miao was imprisoned we understood that not to register her was a mistake, as it impairs our legal means to help.”

Zhang’s case has stirred up long-held frustrations among news assistants who feel they bear great risk sometimes, with little recognition and low pay, for foreign news companies.

One longtime researcher for a Western broadcaster said there is no choice. “You can either waste your life away working for China’s censored local media where you can’t explore any sensitive issues, or you can work for what you actually believe in at a foreign bureau,” she said.

Many complain that there is little prospect for advancement because Chinese citizens are banned from becoming reporters for foreign news companies. Others describe pressure from friends and relatives who view them as spies or unpatriotic for exposing China’s dirty laundry to outsiders.

“There is more risk for us than any one else in the bureau. If things continue to get worse, everyone has a bottom line,” said one researcher for a newspaper from a smaller nation. “For me, if it starts affecting my family members, there’s no way I can continue.”