Reporter Liu Hu was detained in Chongqing by men identifying themselves as Beijing police.
Beijing police have detained a graft-busting journalist who reported on corruption among officials of the ruling Chinese Communist Party from his hometown of Chongqing in southwestern China.
Liu Hu, a reporter with Guangzhou's Modern Express newspaper, was detained in Chongqing Friday around noon by men identifying themselves as Beijing police, while his account on the hugely popular social media site Sina Weibo was suspended.
His detention comes as the trial of disgraced former Chongqing Party chief Bo Xilai entered its second day in the eastern province of Shandong, but no connection between the two cases was immediately apparent.
A reporter who answered the phone at the Modern Express newspaper editorial offices on Friday said Liu's colleagues were shocked and surprised at the news.
"I saw that his wife sent out a tweet around noon saying he had been taken away for investigation by Beijing police," said the reporter, who declined to give their name.
"He always dared to speak up and dared to take action," the reporter said. "His is a fiery sort of personality typical of people from Chongqing."
"I always thought he was a good sort of person, and he won a lot of respect from [his colleagues]," the reporter said.
Among the cases of corruption probed by Liu was that of Ma Zhengqi, deputy director of the National Chamber of Commerce.
Some analysts saw his detention as part of an ongoing crackdown on whistleblowers and activists who called on Party officials to reveal details of their assets, and those of their families.
Guangzhou's cutting-edge Southern Metropolis website posted a report about Liu's detention, but it was later unavailable from the same address.
Calls to the editor-in-chief of the Modern Express went unanswered during office hours on Friday.
Liu had also exposed the case of Shanghai High People's Court president Cui Yadong, accusing him of stealing tons of Maotai liquor, a favorite at official banquets, during his tenure in the southwestern province of Guizhou, netizens said, although RFA was unable to verify these claims.
"Liu Hu was taken away in handcuffs by Beijing police," tweeted Sina Weibo user @zuojiacaojunshu, who also sent the original tweet exposing Cui.
"It always comes to this; the whistleblowers get arrested by police and have no peace ... and yet no official body will come out and say whether or not Liu Hu's reports are correct, or whether those officials really are corrupt."
Guangzhou-based rights lawyer Tang Jingling said Liu's detention was part of a continuing crackdown on freedom of expression.
"I think it has to do with the recent crackdown on 'rumor-mongering' online," Tang said.
"They ... have recently targeted very active netizens and news professionals, who make it their business to expose official scandal."
"Their use of criminal measures ... shows they wish to prevent netizens from exposing the truth about official corruption," Tang added.
Liu's detention comes after the unofficial detention of a veteran journalist by state security police in Beijing, after he campaigned for the release of anti-corruption activist Xu Zhiyong.
Chen Min, best known by his pen-name Xiao Shu, was detained by Beijing's state security police and held at a guesthouse earlier this month.
He said at the time that the detention of anti-graft activist Xu Zhiyong and 15 other activists who had called on China's leaders to reveal details of their assets constituted an attack on China's nascent civil society.
Meanwhile, the authorities have shut down more than 100 privately run websites since May 9, according to the New York-based Committee to Protect Journalists (CPJ).
Some of the closed sites were accused of "blackmailing" companies or individuals by threatening to publish negative information about them, it said.
Leading transparency campaigner Xu Zhiyong was detained by Beijing police in July on charges of disrupting public order, in a widening crackdown on activists who have called on government leaders to declare their assets, activists and lawyers said at the time.
Xu, a key figure in the nascent "New Citizens" anti-corruption movement, is currently being held in the Beijing No. 3 Detention Center.
A teacher at the Beijing Postal University who has served as a delegate to the Haidian district-level People's Congress, Xu has also been active in fighting for the rights of the children of migrant workers to be educated and to sit exams in the capital.
His pro-democracy group, the Open Constitution Initiative, was banned after Xu was targeted by the authorities for "tax evasion" in 2009. He has been repeatedly called in for questioning and held under house arrest since then.
Beijing-based lawyer Li Fangping said he believed the authorities were proceeding with the case against Xu.
"I think this decision came from very high up," Li said on Friday.
Reported by Yang Fan for RFA's Mandarin Service. Translated and written in English by Luisetta Mudie.