Beijing: A Chinese official was allegedly drowned by investigators who stripped him naked and held him down in a bathtub as they attempted to extort a confession to corruption, state-run media reported on Wednesday.

Yu Qiyi was held down by graft investigators in a tub full of "icy water" several times after his questioning failed to produce satisfactory answers, Beijing Times said, citing a court filing by prosecutors. They only stopped when Yu, 42, the chief engineer of a state-owned company in the eastern city of Wenzhou, stopped struggling, the report said.

He was taken to hospital and died a few hours later. A post-mortem showed he had been made to "imbibe liquids" that caused pulmonary dysfunction and eventually his death, according to a photograph of a forensic document. Relatives also found multiple bruises on his body after his death in April, it added. He had been detained since early March over suspected wrongdoings in a land deal, the report said.

The six investigators who interrogated Yu — five of them from the ruling Communist Party's discipline inspection department and the other one a local prosecutor — have been charged with intentional injury and a trial is pending, the report said. "Yu Qiyi was a strong man before he was detained ... but was skinny when he died," the dead man's wife Wu Qian said.

"He was bruised internally and externally during the 38 days (in detention). He must have been tortured in other ways besides the drowning exposed by the prosecution," she said.