A top Chinese forensic expert says there is little evidence that British businessman Neil Heywood died of cyanide poisoning, casting doubt on Beijing's official narrative of an event that sparked a major political scandal.

The 41-year-old businessman was found dead in a hotel room last November in the southwest city Chongqing. Gu Kailai, the wife of a top Chinese politician Bo Xilai, was later convicted of poisoning him because of an alleged business dispute.

But Wang Xuemi, a respected scientist with China's national prosecutor's office, said in a blog post this week that the court documents and testimony describing Heywood's death are inconsistent with what happens during a cyanide poisoning.

Wang, who is also deputy director of the Chinese Forensic Medicine Association, has told reporters that she did not have special access to the trial and has not seen evidence, but bases her opinion on the government's version of the tightly orchestrated trial.

She says the official accounts of the trial do not include a description of symptoms that Heywood would have suffered as a result of the cyanide, including immediate asphyxia, spasms, and a heart attack.

The comments of Wang, who has been praised by Chinese state media for her work as a forensic expert, are a rare example of a government official expressing dissent and are likely to embarrass China's Communist leaders.

The scandal has come at an especially sensitive time for the Communist Party, which in just weeks will hand over power to a new generation of leaders.

It has already wrecked the career of Bo Xilai, who had been considered a favorite to attain a top position in the new party leadership. Though he has been stripped of his party posts, Bo has not yet been charged with a crime.

It is not the first time that observers have expressed doubt about what seem to be inconsistencies in the trials of Gu Kailai and Wang Lijun, the former Chongqing police chief who was convicted of covering up the murder.

Observers say the outcomes of the blockbuster trials were almost certainly predetermined by the Communist Party, which exercises strict control over China's judicial system. Some have speculated that the charges against Gu may be part of an attempt to ruin the career of her husband, Bo.

In her blog post, the forensic expert Wang did not speculate on why the court reached its conclusion and did not express doubt that Gu killed Heywood. She later told news outlets that she had no political motivation for stating her opinion.

Her blog entry, posted Wednesday, has since disappeared.