By Michael Bristow
BBC News, Beijing
Activist Huang Qi has spent a decade fighting for people's rights
Chinese activist Huang Qi has been sentenced to three years in prison for "illegally holding state secrets".
Mr Huang was arrested after helping families whose children died during the earthquake in Sichuan in May last year.
The activist's wife, Zeng Li, said the verdict was "revenge" for his involvement in the earthquake cases.
Amnesty International said Mr Huang was a victim of China's "vague" state secrets laws and should be released immediately.
The verdict was delivered at a 10-minute hearing at Wuhou District People's Court in the city of Chengdu - although there were few details given about the charge.
School buildings collapsed
The activist's wife and mother were allowed to enter the court to hear the sentence, the maximum jail term for this crime.
Zeng Li said: "This is clearly revenge because he helped parents who lost their children during the Sichuan earthquake."
She said any government information that her husband had was freely available to the public.
Mr Huang was taken by the police in Chengdu in June 2008 and has been held in custody ever since.
He was giving advice to the families of five dead children who wanted to bring a legal case against the local authorities following the earthquake.
In some places schools were the only buildings to collapse and many believe this was because they were shoddily built. China's central government denies the accusation.
"The Chinese government is penalising someone who is trying to help the victims of the Sichuan earthquake," said Sam Zarifi, Amnesty International's Asia Pacific director.
"Huang Qi should be treated as a model citizen, committed to the rule of law, but instead he has fallen victim to China's vague state secrets legislation."
Amnesty said the activist had been treated badly while in custody and denied proper medical help.
"According to local sources, the police interrogated Huang Qi for many hours at a time, sometimes depriving him of sleep," said the rights group.
Huang Qi has championed the rights of ordinary people for a decade and has been previously been prosecuted.
He served a five-year sentence for "inciting the subversion of state power" in connection with material published on his website.
He is not the only activist to investigate the Sichuan schools issue - and not the only one to be prosecuted for his efforts.
Tan Zuoren called for volunteers to travel to Sichuan to compile a list of pupils who died when their schools fell down. He was tried in August and is awaiting the verdict.