Ousted Communist Party official Bo Xilai called his former police chief a liar and “vile character” in court Sunday and denied accusations of covering up a murder committed by Bo’s wife.

The confrontation at Bo’s trial brought together Bo and former right-hand man Wang Lijun, who together once ran Chongqing — one of China’s major cities — with an iron fist. For years, the duo presented themselves as a courageous crime-fighting administration, even as darker tales emerged of their corruption and application of extralegal methods on both organized crime and legitimate businesses.

What ultimately brought down Bo was a break in his close relationship with Wang after the death of a British businessman, which filled Wang with such fear that he fled to a U.S. consulate and disclosed the devastating link between the death and Bo’s wife. Bo’s subsequent downfall — from rising star contending for the highest circle of power in the party to the disgraced target of a party purge — triggered one of the biggest political scandals in the history of modern China.

Wang said in testimony Saturday that investigators in his police department were pressured by Bo to stay quiet about his wife’s murder of British businessman Neil Heywood, including one officer who was brought to Bo’s home and forced to sign a document absolving Bo’s wife, Gu Kailai, of any role in Heywood’s death.

Wang described a confrontation with Bo during which Bo said he could not accept Wang’s assertions that Gu had killed Heywood. He said Bo punched him in the left ear so hard that it left his mouth bleeding and liquid dripping from his ear.

Wang explained the reasoning that led him to flee to the U.S. consulate.

“It was very dangerous at the time,” he said. “I was the victim of violence, and then close colleagues and those investigating the case had disappeared.”

Bo on Sunday called Wang’s testimony “totally unreliable and full of deception and nonsense.”

About the confrontation Wang described, Bo dismissed it as a slap, not a punch, saying, “I never practiced boxing, and I don’t have such strong hitting power.”

Bo faces charges of bribery, corruption and abuse of power. Many believe a guilty verdict has been predetermined, but that has not damped interest in his trial, especially after the government began posting online transcripts, videos and photos from the proceedings.

The online posting has allowed authorities to present the highly politicized trial as a transparent affair even as it maintains tight control over what information is released, with all media banned from the proceedings except for state outlets heavily controlled by the party.

The trial was originally announced as a two-day affair but will continue for a fifth day Monday, a highly unusual development in China, where criminal proceedings are often over in a matter of hours.

Liu Liu contributed to this report.