Student ID tags are placed on the ground at Juyuan Middle School following the May 12, 2008, earthquake in Dujiangyan, in China’s southwest Sichuan province, in this May 17, 2008, file photo. A Chinese court Tuesday sentenced an activist who investigated the deaths of thousands of schoolchildren in the massive 2008 earthquake to five years in jail for inciting subversion of state power, the man’s lawyer said.

Beijing ? A Chinese activist who investigated the deaths of thousands of children crushed in their schools during the Sichuan earthquake was sentenced Tuesday to five years, underscoring the government’s determination to suppress questions about why the buildings fell.

Many have asked whether poor construction was responsible for the staggering number of children killed in the May 2008 temblor, which took 90,000 lives. Parents have protested frequently, and authorities have reacted severely to such demonstrations, jailing, harassing and threatening participants.

The United States quickly condemned Tuesday’s conviction of Tan Zuoren, and a human rights activist said the case was the latest example of how China uses its vague subversion laws to silence dissent.

Tan, 56, was convicted of inciting subversion of state power and handed the maximum sentence of five years’ jail by the Chengdu Intermediate Court in southwestern China’s Sichuan province, his attorney Pu Zhiqiang said.

Tan and others have raised the possibility that shoddy construction — possibly fostered by corrupt officials who failed to enforce building codes — caused some schools to collapse in the quake while buildings nearby remained intact.

The government was widely praised for its response to the quake, which came just months before it was set to host the Olympic Games in Beijing, a time of intense scrutiny from the outside world. Authorities were eager to keep the focus on their massive rescue and relocation efforts and moved quickly to quash the politically sensitive theory.

Since then, they have kept up their campaign to silence those who pressed the issue — many of whom are parents who lost their only children. Protesters have been detained, harassed and threatened by police and thugs thought to be paid by officials.

For months after the May 12 temblor, China refused to provide an estimate of how many children had been killed in schools, prompting Tan to start his own investigation in December of that year. He hoped to have a figure before the first anniversary of the quake but was detained in March 2009. His initial estimate was that at least 5,600 students were among the dead.

The government finally announced its own official figure in May last year, saying that 5,335 students were believed to have perished in classrooms.

The court’s ruling against Tan makes no mention of his quake research, but his supporters and human rights groups say they believe he was targeted because of the project.

The court found Tan guilty of inciting subversion for drawing attention to the deadly 1989 military crackdown on pro-democracy demonstrations in Beijing’s Tiananmen Square, Pu said. The ruling cited an essay written by Tan in 2007 about the protests and a 2008 blood drive he helped organized to commemorate the demonstrations, which are also extremely sensitive in China.

“The Chinese government doesn’t seem to understand that criticism is not the same thing as incitement, and that criticism of individual officials or government agencies is not the same thing as calling for the overthrow of the government,” said Joshua Rosenzweig, research manager for the U.S.-based Dui Hua Foundation. “This law is being used in a quite arbitrary and irresponsible way, simply as a tool to silence opinions that the government doesn’t want to hear.”

Lu Shihua, father of a 16-year-old girl who died in the collapsed Beichuan Middle School, said Tan was “a man with a sense of justice” and added that he thought the court’s ruling was “quite extreme.”