SAN FRANCISCO A Chinese couple sued Yahoo and its Chinese affiliates on Wednesday, alleging the Internet firms provided information that helped the Chinese government prosecute the man for his Internet writings.
Wang Xiaoning was sentenced to ten years in prison last year for "incitement to subvert state power" after he e-mailed electronic journals advocating democratic reform and a multi-party system.
His house and computer were searched in 2002.
In the complaint filed in U.S. District Court for Northern California, Wang and his wife Yu Ling charged the Internet firms turned over details to prosecutors that helped identify him to authorities.
"While in custody, Plaintiffs were subjected to torture and cruel, inhuman or degrading treatment, including arbitrary, prolonged and indefinite detention, for expressing their free speech rights and for using the Internet to communicate about democracy and human rights matters," the filing said.
The suit, advanced by the World Organization for Human Rights USA, based in Washington D.C., said Yahoo benefited financially by working with authorities. China is the world's second largest Internet market.
"Defendants had every reason to know and understand that the electronic communication user information they provided to authorities could well be used to assist in the infliction of such abuses as arbitrary arrest, torture, cruel, inhuman or other degrading threat and prolonged detention and/or forced labor," it said.
In a statement, Yahoo said it was distressed that Chinese citizens had been sent to prison for expressing their views on the Internet.
"However, the concerns raised about the Chinese government compelling companies to follow Chinese law and disclose user information are not new," it said. "Companies doing business in China must comply with Chinese law or its local employees could be faced with civil and criminal penalties."
The lawsuit came on a day Yahoo shares fell more than 11 percent after the Internet firm's earnings announced on Tuesday fell below expectations.
The suit names Yahoo, its Hong Kong subsidiary and Alibaba.com, China's largest e-commerce firm, as defendants. California-based Yahoo bought a 40 percent stake in Alibaba for $1 billion in a 2005 deal.
Yahoo said the U.S. government should seek to lobby for political prisoners in China.
"We call on the U.S. Department of State to continue making this issue of free expression a priority in bilateral and multilateral forums with the Chinese, as well as through other tools of trade and diplomacy, in order to help secure the freedom of these dissidents," the firm said.