A top Chinese government forensic scientist has questioned the official cause of death of murdered British businessman Neil Heywood.
Wang Xuemei said the conclusion reached by Chinese authorities that Mr Heywood died from cyanide poisoning lacks sufficient evidence.
The comments by Mr Wang, who is with the government's top prosecutors' office, casts doubt on the official version of a scandal that reached into the upper levels of the Communist Party.
Mr Heywood's murder is at the centre of the scandal, which has seen Chinese politician Bo Xilai ousted from the leadership.
Mr Bo's wife, Gu Kailai, was given a suspended death sentence last month after confessing to murdering Mr Heywood over a business dispute by pouring cyanide into his mouth.
Earlier this week, the Chinese ex-police chief who sparked the scandal when he disclosed the murder, was jailed for 15 years.
Wang Lijuan was convicted of defection, abuse of power, and other crimes after visiting the US consulate in Chengdu in February and revealing that Mr Heywood, who was found dead in November, had been murdered and that the wife of his boss was involved.
Mr Bo was chief of the Communist Party in the south-western city of Chongqing.
He was sacked in February having once been considered a strong contender for a top position.
Mr Heywood's death in a hotel was initially ruled an accident and put down to alcohol abuse, although friends insisted he was not a heavy drinker.