The  man who allegedly killed six Shanghai police officers with a knife was yesterday formally charged with their murders.

City prosecutors laid the charges against Yang Jia, 28, an unemployed loner from Beijing. He is also accused of wounding four others at the Zhabei District Public Security Bureau last Tuesday.

The Shanghai Public Security Bureau said yesterday Yang was "completely responsible" for his actions following expert testimony that ruled out the possibility he was mentally unstable during the attacks.

The bureau said Yang launched the attack to exact revenge over being questioned by Zhabei police officers last October after he was suspected of stealing a bicycle.

On October 5, Yang was stopped and questioned by a patrol police officer of the Zhijiang Road W. Police Station in Zhabei District over a suspected stolen bike.

When asked to show his ID card and provide information about where he rented the bike, Yang refused to answer and reportedly abused other officers and resisted detention efforts, the bureau said.

Early next day, Yang was released after it was established he had just rented the bike.

Since then, he had complained to police numerous times by e-mail and demanded compensation for mental anguish, the bureau said.

On October 16, Shanghai police officers went to Beijing to see Yang in a mediation effort. However, Yang insisted on the dismissal of the police officers who questioned him and demanded 10,000 yuan (U.S. dollars 1,459) in compensation.

Police officers again went to Beijing to try and pacify him on March 15 this year. Yang rejected all offers.

A police inquiry showed that Yang came to Shanghai and stayed at a hostel about 20 meters from Zhijiang Road W. Police Station between June 12 and 23 to monitor the premises by telescope.

On June 26, Yang returned to another city hostel, the police bureau said. He bought a knife, a tear-gas spray, a hammer, a dust mask, a mountaineering pole, rubber gloves and a lighter.

About 9:40am last Tuesday, Yang carried eight bottles full of flammable liquid and set five of them alight outside the gate of the Zhabei District office as a diversionary tactic.

Yang allegedly stabbed a security guard, Gu Jianming, as he tried to intervene. Yang then allegedly attacked four police officers in the lobby and in a duty room on the first floor.

These four men were pronounced dead in hospital. They have been identified as Ni Jingrong, 47, Fang Fuxin, 50, Zhang Yijie, 56, and Zhang Jianping 47.

Yang then allegedly went to the 9th, 10th, 11th and 21st floors by the staircase and stabbed five other officers. Xu Weiya, 48, and Li Ke, 49, succumbed to their injuries.

Meanwhile, a suspect has been detained for posting false information on the Internet that said Yang was beaten up and kicked in the genitals by Zhabei District police.

Cheng Jiulong, a spokesman for the Shanghai bureau, identified the suspect as Jia Xiaoyan, a native of Suzhou in Jiangsu Province.

"Jia confessed he started the rumor in order to become more popular with the online community," Cheng said.

(Shanghai Daily July 8, 2008)