BEIJING (AP) — A Tibetan writer who had signed an open letter critical of the Chinese government's quake relief efforts in western Qinghai province has been detained by police, according to a family friend.

The writer, who publishes under the name Zhogs Dung but whose real name is Tagyal, was among eight authors and intellectuals who signed a letter dated April 17 that expressed sorrow for the disaster that left more than 2,000 people dead — most of them Tibetan — but also urged wariness of Chinese government relief efforts.

Last Friday, a half dozen police officers showed up at the Qinghai Nationalities Publishing House in the regional capital of Xining, where he worked, and escorted him away, according to a blog post written by a friend. They searched his home and library, confiscating his computers.

Afterward, they showed his arrest warrant to his wife, and asked her to bring bedding for him. When his two daughters went to the police station they were not allowed to meet with him, the posting said.

There was no way to independently confirm the account. On Monday, the Xining Police Department refused to answer questions regarding his whereabouts, saying it had no comment. The police referred questions to the Ministry of Public Security.

The letter urged people to help victims by offering food, clothes and medicine but warned them not to donate funds to relief organizations, warning of possible corruption.

"Better to send (money) to the disaster zone with people you trust, because nobody can say there is no corruption," said the letter, which was posted on several websites, including the overseas Boxun.com, which is critical of the Chinese government.

"Just as the news from the mouthpiece for the (communist) party organizations cannot be believed, we dare not believe in the party organization, which issued the order stopping people from going to the disaster zone for political reasons," it said.

It's unclear whether the open letter was directly connected to his detention. The Chinese government has been at pains to quash any criticism of its relief efforts in the Tibetan region, where a total of 2,220 people were killed, according to the latest government figures.

Beijing has sought to take credit for much of the rescue work, portraying relief efforts as a government undertaking in this remote Tibetan region where residents have frequently chafed under Chinese rule. Tibetan resentment over political and religious restrictions and economic exploitation by majority Han Chinese have sometimes erupted in violence.

State media largely played down the role of thousands of Tibetan Buddhist monks who worked alongside soldiers to rescue survivors and dig out the dead.

On April 19, the Qinghai provincial government had issued a ban against pornography and what it called "illegal publications." According to state media, Zhang Chengwei, head of the anti-pornography and illegal publications office, said that pressure must be used to "prevent unlawful elements from using illegal publications to disturb social stability and to disturb and sabotage disaster relief."

Zhogs Dung, 45, is considered a leading intellectual and thinker who in the past has written books that largely aligned with the Chinese government's views on modernization, religion and culture in Tibet. However, he published a book this year that was far more critical of the government in the wake of anti-government riots in Tibet in 2008.

Robbie Barnett, director of the modern Tibetan studies program at Columbia University, said the book may have been another reason for the government to target him.

Zhogs Dung was seen by fellow Tibetans as an "official intellectual" who took the Communist Party's view, for which he was widely criticized. But a few months ago, he quietly published a book called "Distinguishing Sky from Earth," in which he said the March 2008 riots, the largest anti-government protests in Tibet in decades, were a turning point for Tibetans and their national spirit.

In the book, he advocated "non-violent resistance" to obtain greater rights for Tibetans, Barnett said. He seemed to sense he was crossing a dangerous line, saying he expected to be arrested for his views.

"Here was someone who had supported the government. Now he himself is being detained by the state. This will be understood as China losing even those it could have allied with," Barnett said.

China is hugely sensitive to issues regarding ethnic rights. A Mongolian rights activist who had been invited to speak before the United Nations in New York was arrested on April 18 at the Beijing airport, according to a U.S.-based rights group.