Human rights advocates are concerned that a Chinese citizen journalist, expected to be released from prison, might face home detention.
The lawyer-turned-citizen-journalist, who reported on the early stage of the COVID-19 pandemic in Wuhan, was expected to soon walk free after completing her four-year sentence.
But activists said they were yet to receive confirmation of Zhang Zhan's release.
"We have received warning signals that some activists and lawyers, based in China, have been threatened in recent weeks by Chinese authorities not to raise Zhang Zhan's case internationally," Reporters Without Borders advocacy officer Aleksandra Bielakowska said.
A Shanghai court sentenced Ms Zhang to jail in December 2020 for "provoking trouble" after she travelled to Wuhan as the Chinese government placed the city under strict lockdown early in the pandemic.
Ms Zhang uploaded dozens of short, shaky mobile phone videos to YouTube, showing deserted streets and crowded hospitals.
She also visited a police station where Li Wenliang, a doctor who issued an early warning about COVID, had been reprimanded and tried to ask about his case.
Jane Wang, a UK-based advocate who has campaigned for Ms Zhang's release, fears that she may be sent to an undisclosed location.
"I understand that her parents and brother have been under enormous pressure and warned severely not to give media interviews."
She said she was aware of at least one Shanghai-based activist who was summoned by the police for discussing Ms Zhang's release plans.
Concerns for Zhang Zhan's health
Ms Zhang's health remains a concern after she staged a partial hunger strike.
She was hospitalised in July 2021 weighing less than 40 kilograms.
Ms Zhang's parents and brother went to Shanghai at the time but were only permitted to speak with her over the phone.
"We know that she has been continuing the partial hunger strike and that her health status has improved slightly, but it has not been cured completely," Ms Bielakowska said.
"And she has not received appropriate health support from the authorities."
Ms Wang said she was worried Ms Zhang would become a prisoner in her own home.
"If she is placed under house arrest she will have little chance of getting urgently-needed, long-overdue medical treatment," she added.
China's Foreign Ministry spokesman Wang Wenbin told reporters on Monday he had no "relevant information" on the matter when asked about her case.
'Picking fights and provoking trouble'
Analysts said Ms Zhang's sentence for "picking fights and provoking trouble", a vaguely defined charge often used in political cases, underscored China's heightened censorship to control the narrative at the start of the pandemic.
However, Ms Zhang represents just one of many silenced critics.
The Chinese government has faced accusations of covering up early missteps and delaying the release of critical information that would have helped slow the spread of the virus.
"She was a citizen journalist who was doing something that had the potential to implicate or co-implicate the Chinese government in some way, as not having done its job properly," remarked John Garrick, a law fellow at Charles Darwin University.
Yanzhong Huang, a senior fellow at the Council on Foreign Relations, highlighted Ms Zhang's courage to travel and report on the early stages of the pandemic despite the risk of arrest.
He pointed to the shift in China's narrative on the Wuhan lockdown.
"Now it's all about the 'historic lockdown', and how effective the government measures were to stop the domestic transmission rate," he said.
