Almost a year to the day after she was seized from her Beijing home and spirited into secret detention, Chinese police say they have released a young legal assistant on bail.

Zhao Wei, 24, was taken into custody on 10 July 2015, on the second day of what activists have described as an unprecedented government offensive against China’s human rights lawyers.

Before her detention Zhao had worked for Li Heping, one of China’s most prominent human rights lawyers.

Police in the city of Tianjin, where Zhao was being held, announced her release on bail on Thursday morning, on the eve of the crackdown’s one-year anniversary.

A post on the police force’s official Weibo account said Zhao was being bailed as a result of her “candid confession” to unspecified crimes and her “good attitude”.

Like most of the more than 20 lawyers and activists still in custody, Zhao was being held on charges of political subversion.

The idealistic young legal assistant’s detention sparked outrage in and outside China, and Zhao Wei’s supporters greeted the announcement of her release with contempt. “What crime did she commit?” read one angry comment under the police’s social media post. “History will judge you,” said another.

In a message posted on her Weibo account on Thursday afternoon Zhao appeared to confirm her release and said she was “very well”. “The afternoon sunshine feels so nice. It feels so good to breathe freely,” Zhao wrote.

“It has been both a long and a short year. I have a lot of feelings but at this moment … I just want to enjoy the peace and the happy days with my dad and mum,” she added.

In a brief telephone interview, You Minglei, Zhao’s husband, said: “I am quite happy with the news but releasing her on bail doesn’t mean the case has been closed.”

Activists say Zhao will still face the prospect of charges despite her release.

Calls to the phone of Zhao Wei’s mother, Zheng Ruixia, went unanswered on Thursday afternoon. However, speaking to the Guardian in January Zheng rejected the accusations against her daughter.

“She did not do it for sure. Zhao Wei loved this country,” she said.

“The Communist party is in charge. Whether you have committed a crime or not all depends on what the Communist party decides,” Zheng added. “Even if you didn’t commit a crime, if [the party] says you did, then you did. End of story.”

William Nee, Amnesty International’s Hong Kong-based China researcher, said Zhao had been the victim of a preposterous and unjust “national security witch hunt”.

Nee called on Beijing to drop all charges against Zhao and to “immediately and unconditionally release all the other lawyers and activists who have been caught in this crackdown”.

Additional reporting by Christy Yao