Public security officials in central China's Hubei Province on Saturday confirmed that a mass food poisoning that killed six people last weekend was caused by misuse of a highly toxic rat poison known as "Dushuqiang".

A specially-formed key task police team, consisting of police personnel from three levels of Hubei Province, Jinzhou City and Gong'an County, made the conclusion.

The investigation found that around midday on Nov. 11, Chen Ruyan, a salvage station worker near the Qingshibei Pump Station of Qinghe Village, Ganjiachang Township of Gong'an County, was preparing lunch.

In the process, Chen found the rice dough he was preparing for making tangyuan, a kind of rice dumplings, was quite watery and he decided to add more rice flour. Unfortunately, he mistook rat poison that had been placed together with other condiments as flour and mixed it into the dough.

Two elderly people collapsed and died about 20 minutes after having consumed the rice dumplings. Six others soon developed symptoms of poisoning and were rushed to hospital. Four later died while under care.

Chen, the cook, also died from poisoning.

The two surviving poisoning victims have been transferred to Jinzhou Central Hospital for further medical treatment. They are still in critical condition.

Investigators found Chen, who used to sell the rat poison for profit, had wrongly placed the chemicals inside the kitchen when he moved his home over to the salvage station.

An autopsy found traces of rat poison in Chen's nails and more than 200 more grams of the same poison in a cupboard at his home.

(Xinhua News Agency November 17, 2007)