Fallen top politician Bo Xilai knew his wife was suspected of murdering a British businessman, Chinese state media implicitly alleged Wednesday, linking him to a criminal act for the first time.

Without mentioning Bo's name, the Xinhua state news agency effectively accused him of rebuking and slapping Wang Lijun after the police chief briefed him on Neil Heywood's murder, suggesting an attempted coverup.

Wang's flight to the US consulate in Chengdu, after his relationship with Bo soured, triggered the biggest political scandal to hit China's Communist Party in years and saw the politician's wife Gu Kailai convicted of murder.

The turmoil, months ahead of a generational leadership handover, exposed rifts in the top echelons of the ruling party.

A day after Wang's trial on charges of defection, abuse of power, bribery and other offences, Xinhua issued an extensive account of the proceedings.

At a meeting in January Wang briefed the "main person responsible" for the Chongqing Communist party committee -- which Bo headed -- on Gu's role in the killing of Heywood two months earlier, it said.

The next day Wang received an "angry rebuke and was also slapped". Within hours, he arranged for subordinates to safeguard key evidence implicating Gu.

A few days later he fled to the US consulate in Chengdu, "feeling he was in a dangerous situation", the report said without specifying the exact nature of his fears.

He "chatted briefly with US consulate staff about environmental protection, education, science and technology and other matters", it said, and "requested the Americans to provide asylum, and wrote an application for political asylum".

Wang told them he "had received a threat to his personal safety as a result of investigating a case", Xinhua said.

But Wang ultimately left the consulate and was taken away by Chinese officials.

He was not seen in public again until state news channel CCTV showed him appearing in court on Tuesday.

Bo, who had come to prominence by espousing a Maoist revival and a hard line against organised crime, saw his political career cut short by the scandal.

Gu Kailai was handed a suspended death sentence last month.

Xinhua's detailed narrative did not use Bo's name at any point. But it was the first time official media have in effect mentioned him in connection with the murder.

He has not appeared in public for months and has been put under internal investigation by the Communist party for "serious" discipline violations.

Xinhua quoted Wang as telling the court: "I acknowledge and confess the guilt accused by the prosecuting body and show my repentance.

"My acts were crimes, and I hope the serious impacts both at home and abroad would be eliminated through the trial. Meanwhile, I hope the trial will issue a warning to society and let more people draw lessons from me.

"For the Party organisations, people and relatives that have cared for me, I want to say here, sincerely, 'I'm very, very sorry, I've let you down.'"