A court upheld a Chinese dissident's five-year sentence for subversion on Wednesday after he investigated the deaths of children crushed in their schools during the 2008 Sichuan earthquake.

The Sichuan provincial high court upheld the ruling in a brief hearing on Wednesday morning, Tan's wife, Wang Qinghua, said by telephone.

Chinese bureaucrats rarely release information about sensitive political cases and court officials reached at two separate departments said they had no information about Tan's appeal.

Muffling questions

The denial of his appeal underscores the government's determination to suppress questions about why so many schools collapsed during the quake, which killed 90,000 people.

According to official figures, almost 7,000 classrooms collapsed, killing 5,335 students, but the government has refused to respond to complaints that many schools were poorly constructed and lacked emergency exits and other basic safety features.

Information seekers: Beaten, imprisoned

Parents of dead children launched a short-lived protest movement, to which authorities — ever vigilant against criticism and potential unrest — responded with jailings and threats. Avant-garde artist Ai Weiwei, who has also investigated student deaths, was detained and beaten by police while attempting to attend Tan's August trial.

In Hong Kong, about 30 human rights activists protested the court's decision on Wednesday outside the Chinese government's liaison office in the semiautonomous territory, which has its own legal system and civil liberties.

Members of the group chanted "Release Tan Zuoren immediately," and one protester was detained after scuffling with police officers trying to stop another demonstrator from throwing tofu at the office.

Hong Kong radio RTHK reported on its website the man was later charged with attacking a police officer and freed on bail of 300 Hong Kong dollars ($38). Hong Kong police didn't immediately return a call seeking comment.

Judge Justice?

Wang said she had seen Tan from a distance in the court room and the two exchanged smiles and waves but weren't allowed to speak. She said the only remarks made during the 10-minute hearing were from the judge.

Tan, 56, who has been detained since April 2009, appeared to be in high spirits and good health, Wang said.

"It's not too hard to take. Just a few hundred days to go," Wang said.

Wang said the couple's daughter, Li Chang, and other supporters were not allowed into the chamber, but were hustled into the courthouse after attempting to film the scene from the street.

Govt. scapegoat

The February ruling made no mention of Tan's quake research, citing instead an essay he wrote about the June 4, 1989 military crackdown on pro-democracy demonstrations in Beijing, and plans to commemorate the anniversary. However, his supporters and human rights groups say they believe he was targeted because of the school project.

Tan had conducted his own investigation into 64 schools flattened by the 7.9 magnitude temblor, which struck a wide swath of mountainous southwestern China and the Tibetan plateau. Before being detained, Tan estimated more than 5,600 students died or were missing, but said that number was incomplete.

Complaints over school construction emerged after classrooms collapsed even as government offices and other buildings nearby remained intact.

The court's upholding of Tan's sentence was widely condemned by human rights groups as a miscarriage of justice and an attack on corruption whistle-blowers.

"This is a politically motivated outcome of a grossly unfair legal process," Catherine Baber, Amnesty International's deputy director for the Asia-Pacific, said in a statement.