Yahoo Inc. provided evidence that was entered in a court case against a writer sentenced to 10 years in prison over pro-democracy essays posted online, a human rights group said Friday.

Human Rights in China said Wang Xiaoning was sentenced in September 2003 on the charge of "incitement to subvert state power," a vaguely defined statute that the Communist Party frequently uses to punish its political critics.

Said also was that Wang, 56, distributed pro-democracy writings authored by him and others by e-mail and through Yahoo Groups, an online e-mail community.

The claim marks the fourth time that the US-based Internet company has been accused by rights groups of providing information that may have helped to jail Web dissidents.

A former engineer in China's weapons industry, Wang had been detained previously for his political activities following the June 4, 1989 military crackdown on pro-democracy protesters in Beijing's Tiananmen Square.

Passages from writings cited in his trial included:"Without a multiparty system, free elections and separation of powers, any political reform is fraudulent." Others called China an "authoritarian dictatorship," and complained of continuing widespread corruption, poverty and workers exploitation, HRIC said.

However, his undoing may have come from writings that appeared to call for the Communist Party's overthrow and his electronic correspondence with the leader of an overseas Chinese political party considered hostile by the communists. Leaders are extremely sensitive to any calls for political organization against them.

Yahoo told prosecutors that Wang's "aaabbbccc" Yahoo Group was set up using the e-mail address bxoguh@yahoo.com.cn, and confirmed that the address was based in mainland China, HRIC said, citing the formal written judgment against him.

However, the New York-based rights group said the judgment does not indicate whether Yahoo provided specific information regarding Wang's identity.

Pauline Wong, a spokeswoman for Yahoo's Hong Kong unit, said she had no information about the case, but that the company requires strict legal documentation before complying with any official request for information.

Even if such information was handed over, Yahoo would not know the nature of the investigation behind such a request, Wong said.

Porter Erisman, a spokesman for Alibaba.com, which acquired Yahoo's mainland China operations last October, said he had no knowledge of any Chinese legal requests prior to the purchase.

"We follow the laws of every company in which we operate," Erisman said.

A clerk at the Beijing Municipal First Intermediary People's Court where Wang was reportedly sentenced said he was not aware of the case. Like many Chinese bureaucrats, the official would only give his surname, Lin.

A female officer at the Beijing Municipal No. 2 Prison where Wang was being held said she could not release any information over the phone.

Allegations that US Internet companies have helped convict Chinese Web dissidents have drawn strong condemnations from the US Congress and other critics.

"The heavy sentence ... imposed upon Wang Xiaoning illustrates the risks Chinese people expose themselves to through no more than the peaceful expression of political views," HRIC said in a statement.