Zhang Zhan was released from prison after serving four years for charges related to reporting on the Covid-19 outbreak in Wuhan, according to a video statement she released on Tuesday, eight days after her sentence ended.

Ms Zhang was sentenced to four years in prison on charges of “picking quarrels and provoking trouble”, a vaguely defined charge often used in political cases, and served her full term.

Yet, on the day of her release, her former lawyers could not reach her or her family. Shanghai police had visited activists and her former lawyers in the days leading up to her release.

In a short video, Ms Zhang said police took her to her brother Zhang Ju’s home on May 13, the day she finished her sentence.

“I want to thank everyone for their help and concern,” she said in a soft voice, standing in what appeared to be an apartment building hallway.

The video was posted by Jane Wang, an overseas activist who launched the Free Zhang Zhan campaign in the United Kingdom and is in contact with one of Ms Zhang’s former lawyers.

However, Ms Wang said in a statement that Ms Zhang still has limited freedom. They became concerned that Ms Zhang would be kept under further control by police even if she was no longer in prison.

The United States Department of State also stated concern over Ms Zhang’s status in the days after she was due to be released.

Ren Quanniu represented Ms Zhang before his license was stripped in February 2021. He said he confirmed the video by speaking with Ms Zhang’s family.

Ms Zhang was among a handful of citizen journalists who travelled to the central Chinese city of Wuhan in February 2020, in the early days of the pandemic, after the government put it under total lockdown.

She walked around the city to document public life as fears grew about the then-mysterious coronavirus.

Other citizen journalists have also spent time in jail for documenting the early days of the pandemic, including Fang Bin, who published videos of overcrowded hospitals and bodies during the outbreak.

Mr Fang was sentenced to three years in prison and released last April.

Another citizen journalist, Chen Qiushi, disappeared in February 2020 while filming in Wuhan.

Mr Chen, in September 2021, resurfaced on a friend’s live video feed on YouTube, saying he had suffered from depression but did not provide details about his disappearance.