Mystery surrounded the violent death of a prominent dairy industry whistleblower, after media reports questioned the official explanation which suggested his wife was to blame.

Jiang Weisuo, 44 - whose efforts to expose milk adulteration in 2006 earned him fame as the industry's "first whistleblower" - died in hospital on November 12, 10 days after suffering two knife wounds, the Xian Evening News reported.

The newspaper cited an unidentified local police source who said Jiang, the general manager of a dairy products plant in Shaanxi province, had been stabbed by his wife during a family dispute. Police had detained his wife as a suspect and are waiting for autopsy results to confirm if the wounds were lethal.

Jiang's prominence as a food safety critic has caused some media outlets to question whether his death was related to his efforts to clean up the industry. Reports have speculated he was attacked after rejecting a blackmailing threat or targeted by a hit-man.

Yesterday, The Beijing News said Jiang's wife - who it identified as Yang Ping - did not stab her husband, and cited an anonymous source "with information".

"Several people were present and it was unclear who did it," the source said. "It probably had to do with monetary matters."

The publicity department of the Xian Yantan District Public Security Bureau, where the case is being handled, could not be reached for comment.

A spokeswoman for Jiang's company confirmed the crime took place at home and said his wife did not attend his funeral on Wednesday.

Wang Weimin , chairman of the Xian Dairy Association, delivered the eulogy at Jiang's funeral and told the Sanqin Daily the victim's death had nothing to do with his criticism of the dairy industry.