Dr Zhang Mingqiang is in cell number 204 of Shanghai's notorious Qingpu prison - sentenced to six years for spying. He worked for US pharmaceutical giant Amgen in charge of research and development at their Asian operations. Caught in the crossfire between Beijing, the US and the EU, Zhang and his case are not openly discussed.
"His feet were black. Frostbite. He's losing his toes. He was in tears," says Seyed Alireza Motavalian, an Iranian former Qingpu prisoner, of the ordeal suffered by fellow prisoner Zhang - who holds dual Dutch-Chinese citizenship and a PhD in medicinal chemistry with Belgium's Leuven University.
For months the two had been locked up in cells next to each other, but contact - apart from "shouting through the walls" - was not possible due to Covid-19 restrictions. Alireza himself served 10 years for a bank fraud charge he says was trumped up. He finally met Zhang in person two weeks before he was released.
Alireza says Zhang, who is in his fifties, asked him to raise awareness of his situation to the outside world.
Marius Balo, a Romanian who spent eight years in Qingpu, describes Zhang as "a buddy with whom he shared an interest in books".
After the Covid lockdown, which resulted in a complete lack of contact with the outside world, mental stress added to Zhang's physical pain, Balo said.
"He had given up all hope on improvement. He was in a state of apprehension."
But Zhang had learned that complaining to visitors triggered immediate repercussions from prison authorities.
Another inmate, an Australian-Chinese named Jack, had told his consul that he "was dying", says Alireza. As a result, the phone line connecting him to the consul was cut and he was placed in solitary confinement for a month.
Zhang, who had an impressive career as medicinal chemist with top functions in companies like Merck, Hoffmann-la Roche and Biotica before he ended up with Amgen, told Alireza that he feared "ending up like Jack".
"You are going home soon," he told him. "Get the word out."
According to Alireza's testimony, Zhang was accused of spying. But according to a source familiar with the case, he was merely involved in routinely "transferring results from local research to Amgen's headquarters in the US" - a strictly regulated proces that "requires prior approval for sample and data exchange - mostly human blood - and tissue samples".
But even with the best compliance work, Chinese authorities could still find fault with Amgen and throw the legal person into prison, the source said.
It is unclear if this resulted in spying charges, he said, but Zhang's role in China "also had a PR/government affairs component, and he might have accidentally touched certain sensitive issues in the process".
Peter Humphrey, a British former journalist-turned fraud investigator was locked up in Qingpu in 2014 for 23 months on charges of "illegally acquiring personal information" of Chinese nationals when looking into a massive fraud case.
Today he runs a support network for foreigners who got caught in China's opaque prison machinery.
Humphrey says that if Zhang's case was treated as spying, most of the trial would have been held in secret - adding Zhang was relatively lucky to be sentenced to only six years given the Chinese counter-espionage law allows for "life and even death sentences".
EU walking a fine line
The case is complicated by the fact that Zhang has a dual Dutch-Chinese citizenship, and in addition works for a major American company.
The EU is walking a fine line to keep relations with China on the right track. Things went south after increasing concern about China's trade practices resulted in Brussels calling China a "systemic rival" in 2019. This came amid growing EU criticism of China's human rights situation, which led to the suspension of a major investment deal in 2021 and Chinese counter-sanctions.
Meanwhile at the instigation of Washington, the Netherlands further limited the export of highly advanced microchip-printing machines made by tech giant ASML, which triggered an angry response from Beijing.
Netherlands lands in crossfire in US-China trade war
Both the Dutch authorities and Amgen refuse to discuss Zhang's case openly. It remains completely unheard of, unlike other high-profile cases involving foreigners charged with spying.
In reponse to a request by RFI, Dutch Foreign Ministry spokesperson Casper Soetekouw said his government was aware of the case and was providing consular assistance.
"We exercise caution in discussing consular matters with local authorities in public," he added.
There are 11 Dutch citizens in Chinese jails according to the 2022 edition of a newsletter on consular affairs published by the Dutch Ministry of Foreign Affairs.
Amgen's director of communications, Jessica Akopyan, responded after repeated RFI requests to say the company did not "comment on situations involving current or former Amgen employees".
'Lack of support'
Alireza, Balo and Humphrey expressed surprise by what they see as a lack of support from Zhang's consulate and company.
"What we have here is somebody who's been abandoned and thrown under a bus by the company that employed him, and also by the Dutch government," says Humphrey.
Alireza points out there was some initial contact with Dutch authorities, but that Covid restrictions shut down all exchange.
"During the pandemic, it was generally more difficult and, in some countries, impossible to visit detainees due to measures taken by local authorities," says Soutekouw, the Dutch spokesperson.
But even after the restrictions were lifted, there was not much progress. A readout from a recent, five-hour meeting between Dutch Foreign Minister Wopke Hoekstra and Chinese counterpart Qin Gang in Beijing does not mention the case.
The prisoners-turned-activists now hope that international attention will help free Zhang.
"I have always been in favor of transparency on such cases and I'm in favour of making lots of noise," says Humphrey.
"They [foreign goverments] actually started doing something to bring me back the moment my case became public," says Balo.
"Until then, they do not really want to get involved and try to help."
Pointing at the case of Canadians Michael Spavor and Michael Kovrig, Humphrey says they "were both falsely tried for espionage after being detained very arbitrarily". However if the government made enough noise, it was may be possible to get some concessions out of China.
"If you say nothing and do nothing, then nothing will happen," Humphrey says.