Chinese politician Bo Xilai initially agreed to a police probe of his wife's role in the murder of a British businessman before abruptly reversing course and demoting his police chief, causing upheavals that led to the downfall of both men, sources said.
The sources' account gives new details of the dramatic breakdown in relations between Mr. Bo, an ambitious leader who cast himself as the crime-fighting boss of Chongqing, China's biggest municipality, and his once trusted police chief, Wang Lijun.
Reuters reported on Monday that Briton Neil Heywood was poisoned last November after he threatened to expose a plan by Mr. Bo's wife, Gu Kailai, to move money abroad.
The scandal is potentially the most divisive the Communist Party has faced since Zhao Ziyang was sacked as Party chief in 1989 for opposing the brutal army crackdown on student-led demonstrations for democracy centred on Tiananmen Square in Beijing that year.
Before his fall, Mr. Bo, 62, was widely seen as a contender for a post in China's top leadership committee, which will be decided later this year.
In a tense meeting on or about Jan. 18, Mr. Wang confronted Mr. Bo with evidence implicating Ms. Gu in the death of Mr. Heywood, a former friend of the Bo family, said two sources with knowledge of police and government information on the case.
Mr. Bo was so angry he ordered Mr. Wang out of the office, but after composing himself he told Mr. Wang to return and signalled that he would let the inquiry proceed, the sources added.
Two or three days later, Mr. Bo backtracked and shunted aside Mr. Wang in an apparent bid to quash the inquiry and protect his wife and his career, the sources said.
Mr. Wang fled to the U.S consulate in the nearby city of Chengdu on Feb. 6 in an apparent asylum attempt, which exposed the rift between him and Mr. Bo and later brought to light official suspicions that Mr. Bo's wife engineered Mr. Heywood's murder.
It is not possible to contact Ms. Gu, Mr. Bo or Mr. Wang. Ms. Gu and Mr. Wang are in custody and Mr. Bo has not been seen in public since March, when he was dismissed as boss of Chongqing, in southwest China. He was stripped of his seat on the Politburo last week.
Ms. Gu is being held on suspicion of committing or arranging Mr. Heywood's murder, though no details of the motive or the crime itself have been publicly released, other than a general comment from Chinese state media that he was killed after a financial dispute.
Shortly before Mr. Bo was removed as party chief of Chongqing, he said his family was being unfairly vilified by rumours he did not specify, and leftist groups supporting him have continued to maintain he is the victim of a plot.
"Bo was shocked and outraged after he learned about the murder. He asked Wang to leave, saying he wanted to be alone and clear his mind," said well-connected Chonqging entrepreneur Wang Kang, citing accounts of the confrontation by city officials.
"When Wang returned half an hour later, Bo said to him that the issue carried too much significance and he would seriously punish his wife, Gu Kailai," Mr. Wang told Reuters in his office, decorated with pictures of himself meeting senior officials, including Mr. Bo's late father, revolutionary veteran Bo Yibo, a comrade of Mao Zedong.
A second source with direct ties to senior officials and police in Chongqing corroborated this account of what police and government officials believe happened.
"Bo Xilai was shocked and outraged, and then later saw what a threat the case was," the second source said, speaking on condition of anonymity because of the sensitivity of the matter.
"So he quickly removed him from the public security bureau three days later," the source added. "For Wang Lijun that was a terrible shock. If you took away his uniform, you stole his life."
Mr. Bo demoted Mr. Wang to the much less powerful role of vice mayor for education, culture and science.
Mr. Bo's move against Mr. Wang led to his police chief dashing into the U.S consulate in Chengdu, near Chongqing, where he spent about 24 hours before leaving into the hands of Chinese central government authorities. Mr. Wang could now face treason charges.
Chongqing officials initially told British diplomats that Mr. Heywood's death was natural. Inside the Chongqing government at the time, police were raising suspicions that it was murder and mr. Bo was moving to silence them, the sources said.
Police believe Heywood was poisoned with a drink at Chongqing's secluded hilltop Nanshan Lijing Holiday Hotel after he threatened to expose a plan by Ms. Gu to move money abroad, the second source and another source with knowledge of the police investigation have told Reuters.
Mr. Bo and his police chief had grown close during their popular campaign to clean up organized crime in Chongqing. Unlike other officials, Mr. Wang could visit Mr. Bo's office without informing security first, said the source with direct ties to senior officials and police.
Mr. Wang personally took over the case when he found several deputies had refused to sign off on the report of Mr. Heywood's death, and he reassured investigators to continue their work even after a connection to Ms. Gu was established, the source said.
"When the special case group realized what they were onto about Heywood, they were worried, but Wang Lijun told them not to worry, he would assume full responsibility for their work. He said others shouldn't be implicated," the source added.
Wang Kang, an entrepreneur who also makes documentaries, cited Chongqing officials as saying police chief Wang Lijun had been unwilling to hand over case materials to Mr. Bo.
"Wang Lijun was Bo's attack dog, but he also had his own ideas," said Wang Kang, who is no relation of Wang Lijun.
"If Wang Lijun was totally loyal to Bo Xilai, he could have destroyed the evidence."