Wang Lijun: the cop at the heart of Chinese political scandal

Hong Kong (CNN) -- The trigger of China's biggest political scandal in a generation, Wang Lijun was once a feared police chief whose crime fighting exploits inspired a TV series.

Found guilty of abuse of power, defection and bribe taking after a two-day trial last week, on Monday he was sentenced to 15 years in jail.

His fall from grace began one evening in early February when Wang arrived at the U.S. Consulate in Chengdu in southwestern China in an apparent asylum attempt.

During a frenzied 24 hours, he reportedly revealed to U.S. officials a jaw-dropping tale of corruption and murder in the nearby municipality of Chongqing involving his boss and the city's mayor, Bo Xilai.

Bo, a charismatic and popular leader, was a contender for a top position in the Communist Party.

Wang was later collected by central government authorities, and city officials said he gone on medical leave following "immense mental stress."

The dramatic events unleashed by Wang have threatened to derail the once-in-a-decade leadership transition at the end of 18th Communist Party Congress, which is expected to take place next month.

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Bo's wife, Gu Kailai, was last month handed a suspended death sentence for the murder of British businessman Neil Heywood, once a friend of the Bo family. Bo's career lies in tatters and he is now under investigation for an unspecified "breach of Party discipline."

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Wang, 52 , was born in a remote corner of Inner Mongolia and spent two years as a "rusticated youth" during the Cultural Revolution in the 1970s.

He first crossed paths with Bo in the northeastern province of Liaoning where he had worked his way up the region's public security bureau and Bo was governor.

After Bo was promoted to the top job in Chongqing in 2007, Wang followed him and was assigned to lead his crime-fighting program.

Under Wang, the "da hei" or smash black campaign reportedly caught nearly 3,000 criminal groups and detained thousands of suspects. It also led to the execution of notorious figures in the city's underworld.

The crackdown, along with economic reforms in the city of more than 30 million, helped burnish the political credentials of Bo, who aspired for a spot in the Party's Standing Committee of the Politburo, a nine-member body that effectively rules China.

Wang's heavy-handed, crime-busting methods were decried as brutal by critics.

At the height of the campaign, Beijing-based lawyer Li Zhuang defended an alleged gang member and discovered police torture during interrogation.

"For eight days and eight nights, my client was repeatedly hung from the ceiling," Li recalled in an interview with CNN in late March.

"He eventually soiled himself. His interrogators ordered him to remove the feces on the floor with his bare hands and use his shorts to wipe it clean. Then they hung him up naked."

As he tried to expose the interrogators' crimes, Li said, he was detained, tortured and promptly sentenced to two-and-a-half years in prison under the direct order of Wang for "fabricating evidence and inciting witnesses."

Wang was also known for his unconventional working style and according to the Chongqing Commercial News, once worked as a taxi driver to gauge public opinion on local security and police issues.

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Wang's two-day trial took place Chengdu on September 24 and 25.

He faced four charges -- bending the law for selfish ends, defection, abuse of power and bribe taking.

Some observers said the jail term appeared lenient given that bribe-taking can carry the death penalty in China, depending on the amount involved and the gravity of the case.

Prosecutors said that Wang knew that Gu was involved in the murder of Heywood but covered up for her.

They added that Wang used illegal surveillance measures, forged documents and accepted massive bribes to secure benefits for other individuals.

Political observers have said that Wang, not Bo, "is probably the most hated" figure in the eyes of the Beijing leadership for attempting to defect.

CNN's Steven Jiang in Beijing contributed to this report