A company that China says is controlled by artist Ai Weiwei was accused of massive tax evasion in the government's clearest disclosure yet about its investigation of the activist detained for more than six weeks.

The investigation also found that Beijing Fake Cultural Development Ltd. had intentionally destroyed accounting documents, the official Xinhua News Agency said Friday, citing unidentified police investigators. The brief report gave no other details and did not quantify the "huge amount" of tax the company is accused of not paying.

Ai's family and supporters have previously dismissed similar accusations, and his wife, Lu Qing, says the company in question is registered and belongs to her, not him. The company handles the business aspects of his art career.

Also Friday, outspoken lawyer and legal scholar Xu Zhiyong was bundled away from Beijing by unknown people, the Hong Kong-based Information Center for Human Rights and Democracy said.

Xu, who was investigated and detained for alleged tax evasion in 2009 but was later released on bail, text messaged a friend that he was "being taken away to the suburbs," the center said Saturday. It said authorities appeared to be revoking Xu's bail in the earlier investigation as part of a new tactic of using charges of economic crimes to silence activists.

Law firms handling sensitive cases and some outspoken individuals have previously been targeted in tax evasion investigations that many see as political persecution. Zhao Yan, a news assistant for The New York Times, was jailed for three years in 2007 on charges of financial fraud.

Ai is among China's best-known artists internationally and helped design the iconic Bird's Nest Olympic stadium. Famed for his groundbreaking art and irreverence toward authority, he was picked up at Beijing's airport on April 3 and is being held under a form of detention known as residential surveillance somewhere outside Beijing.

His detention has prompted an international outcry, and Western leaders have called it a sign of China's deteriorating human rights. His family and supporters say he is being punished for speaking out about the communist leadership and social problems.

Hundreds of lawyers, activists and other intellectuals in China have disappeared or been questioned or detained by authorities since February, when online calls for protests similar to those in the Middle East and North Africa began to circulate.

Before he disappeared, Ai had been keeping an informal tally of the recent detentions on Twitter.

Ai has also spoken critically about a number of national scandals, including the deaths of students in shoddily built schools that collapsed during the 2008 Sichuan earthquake, children killed or sickened by tainted infant formula and a deadly high-rise fire in Shanghai that killed 58 people and was blamed on negligent workers and corrupt inspectors.

Ai's studio home has been searched, with documents and computers seized, and his wife has been questioned by the tax bureau regarding Beijing Fake Cultural Development Ltd.

Lu was permitted to see Ai last Sunday for a brief, monitored meeting that was his first contact with the outside world in 43 days.

Tax evasion allegations against Ai were published last month by Hong Kong's Beijing-backed Wen Wei Po newspaper, which said he was also being investigated for bigamy because he has a young son with a woman other than his wife and that he is suspected of spreading pornography online.

China's Foreign Ministry said previously Ai is under investigation for economic crimes and has accused those complaining about his detention of trampling on China's legal sovereignty.