Yahoo's Hong Kong subsidiary provided information to Chinese authorities that led to the imprisonment of writer Wang Xiaoning on charges of incitement to subvert state power, a human rights group has said.

Wang was sentenced to 10 years imprisonment in September 2003, due in part to writings distributed over the internet. The case only recently came to light, according to HRIC (Human Rights in China), a New York-based group.

Among the evidence cited in the judgement against Wang is information from Yahoo stating that Wang’s "aaabbbccc" Yahoo Group was set up using the mainland China-based email address [email protected], HRIC said.

The Hong Kong subsidiary also confirmed that the email address [email protected], through which Wang sent messages to the Group, was a mainland China-based account, according to HRIC.

The judgement, from the Beijing Municipal First Intermediary People’s Court, didn’t indicate whether Yahoo Holdings or Yahoo China specifically revealed Wang's identity to Chinese authorities, HRIC said. Yahoo China has been operated by since last year, but was not at the time Wang was arrested or sentenced.

Spokespeople for Yahoo in China and Hong Kong did not immediately respond to a request for comment on Friday. The company has said in the past that it must abide by local laws.

This is the second time in three months that Yahoo has been implicated in the conviction of a political writer in China. In February, RSF (Reporters Sans Frontiéres/Reporters Without Borders), a journalism watchdog group based in Paris, said Yahoo provided information about an email address used by Li Zhi, a political activist and former government official convicted and sentenced to eight years. Police may have identified Li by using the email address to find his IP address and then location, RSF said.

China regularly prosecutes political activists who distribute antigovernment material via email or on websites.