BEIJING, July 3, 2009 (AFP) - Furious relatives of a Chinese woman being treated for swine flu stoned an ambulance in a rampage at the hospital after she died of electric shock, state media reported.

More than 20 relatives attacked the No. 1 People's Hospital in east China's Hangzhou city on Thursday, a day after the 34-year-old woman was found dead, the Xinhua news agency said.

Suspicious that the woman had been electrocuted, they pelted the ambulance with rocks and damaged other property before leaving, according to Xinhua.

Hangzhou police Friday said an autopsy had showed that electric shock was indeed the cause of death, the agency said in a separate report, but provided no other details.

News of the woman's death had initially sparked concern that she might be China's first fatality from the A(H1N1) virus.

However, Xinhua reported that the woman, who was admitted to hospital on June 23, had shown no symptoms of swine flu at the time of her death, except for an occasional cough.