The rights group Dui Hua said Gu might walk free, on medical parole, in as little as nine years, after a court spokesman said her actions reflected ''psychological impairment''. The court went out of its way to publicise her co-operation, including admitting every aspect of the prosecution case and informing on the ''serious crimes of others''. Gu's once-powerful and divisive husband, Mr Bo, is being detained by the Communist Party's discipline apparatus on unspecified ''serious'' violations. Many close political observers and lawyers in Beijing believe Gu's conviction was the result of a complex deal involving the top leadership, which paves the way for her husband possibly to be charged with covering up the murder while insulating other powerful figures from the fallout. The official court account says Gu murdered Heywood to protect her high-living son, Bo Guagua, after Heywood exacerbated a financial conflict between the two by making a verbal threat. But what it did not say is that she might never have been caught if not for the calculated treachery of her husband's right-hand man, Wang Lijun, China's most famous policeman.

Observers of the seven-hour trial on August 9 said the court heard how Gu had confided in Mr Wang about her plans to eliminate Heywood and Mr Wang did nothing to dissuade her. Mr Wang, knowing a central-level investigation was closing in on him, and therefore in desperate need of a political bargaining chip, initially agreed to do the job for her. ''They would lure [Heywood] to Chongqing, then use the excuse of his resisting arrest as a drug dealer to shoot him dead on the spot,'' says an unofficial account of court proceedings by a university student, Zhao Xiangcha, which has been broadly corroborated by others in the courtroom. But then Gu broke the first rule of survival in the Chinese bureaucracy: that allies must be equally vulnerable to each other. ''Wang Lijun at first took part in the plot, but later on, perhaps fearing the risk, did not want to continue his participation,'' says the Zhao account. When Mr Wang backed out of the shooting plot she discussed her new poisoning plans with him on November 13, hours before performing the deed. The next day she gave him a full debrief - presumably so Mr Wang could arrange the cover-up - and Mr Wang secretly recorded the explosive conversation.

Mr Wang's police team performed an initial pantomime investigation, then declined to open a criminal file, while he personally secured a sample of Heywood's blood from his heart, according to the Zhao account. On February 6, after Mr Wang fell out with his patron, Mr Bo, he fled to the US consulate in Chengdu, carrying evidence of the crime and its sordid detail. That evidence brought down Gu and Mr Bo, and will probably earn Mr Wang a lenient sentence when he goes to court, probably for treason. Yesterday four of Mr Wang's senior associates received prison terms of between five and 11 years for covering up the murder. Gu's accessory, a family retainer, Zhang Xiaojun, 33, was sentenced to nine years' jail. Mr Zhang told the hearing he wanted to say ''sorry'' to the relatives of the victim. ''I really know that I did wrong.''

Gu, in contrast, focused on the harm she had caused to the Communist Party's reputation. ''The case has produced great losses to the party and the country, for which I ought to shoulder the responsibility, and I will never feel at ease,'' she said. Many observers, on the left and right of Chinese politics, have ridiculed evidentiary and logical gaps in the prosecution's case. ''Lies have to be used to cover up lies, leading to an impossible situation where the story doesn't hold together and it becomes a satire of justice,'' wrote He Weifang, professor of law at Peking University, on his blog.