The text message Fan sent Zhang is shown in court.

The parents of a boy who killed himself in a suicide pact arranged over China's most popular instant messaging service, QQ, are suing its owner, Shenzhen-based Tencent Holdings Ltd, in Zhejiang province, Qianjiang Evening News reported over the weekend.

The trial, which began on Thursday in a district court in Lishui, Zhejiang province, has provoked concerns over what sort of liability or accountability Internet service providers have in preventing suicides.

The parents of the boy surnamed Fan have blamed Tencent for failing to exercise effective control over the use of harmful words. Also named in the lawsuit is a man surnamed Zhang, who is accused of inducing the son to commit suicide together, then deciding not to, and not trying to prevent the son's death.

According to the Qianjiang Evening News, this June, Fan, a 20-year-old Shanghai university freshman, responded to a suggestion to commit suicide made by 22-year-old university student Zhang in Lishui through QQ.

The morning of June 22, Fan went to Lishui and met Zhang at the railway station. They then bought some charcoal, alcohol, a brazier and some beer and took them to a hotel room where they locked themselves inside, closed the windows, put a strip of adhesive tape under the hotel room door and lit the charcoal in an attempt to kill themselves by inhaling carbon monoxide.

Zhang, however, got a headache after inhaling the carbon monoxide and left the hotel room at about 5 pm, but Fan insisted on remaining in the room.