Image caption Bo Xilai was one of China's most flamboyant leaders

A police investigation into the family of top Chinese politician Bo Xilai led to his downfall, leaked audio suggests.

The recording is apparently of senior party officials being told of Mr Bo's anger over the investigation. He reacted by demoting the police chief in Chongqing where he was party leader.

Mr Bo was removed last week from his post as party secretary in the city.

Many had thought him in line for promotion in a leadership reshuffle.

Family 'rumours'

The investigation appears to have sparked a chain of events that led to the 62-year-old's demise, one of the most important political dramas in China in recent years.

It suggests there is a fierce battle taking place ahead of the leadership change, expected to happen at the Chinese Communist Party's 18th congress later this year.

The audio recording, which was posted on the internet, seems to have involved senior officials in the western city of Chongqing.

They heard how the city's police chief, Wang Lijun, told Mr Bo in January that his family was being investigated. The politician apparently reacted angrily and demoted Mr Wang, disregarding established practices.

There have been rumours about Bo Xilai's family for some time, many centred on his son, Bo Guagua.

He studied at one of Britain's most expensive private schools, Harrow, before going on to Oxford University.

Photographs that appear to show him enjoying himself at parties have whizzed around internet sites.

Speaking at a political meeting just before he was removed from office, Bo Xilai hit back at the rumours surrounding his family.

He claimed that his wife and son had no assets, adding that his son's schooling was paid for by a scholarship.

Reports that Bo Guagua drives a red Ferrari were also false, he said.

US consulate visit

But the audio recording of the Chongqing meeting suggests the rumours were at least significant enough for an investigation.

Those at the gathering were told that after his demotion, Mr Wang fled to the US consulate in Chengdu, a few hours' drive from Chongqing, because he feared for his own safety.

The police chief's visit to the consulate is already an established fact. This recording suggests the reason behind it.

Mr Wang eventually came out of the consulate and was detained.

It is difficult to verify the authenticity of the recording - or how it was made and why it was released.

But Li Yuanchao, head of the communist party's organisation department, confirmed to Chongqing officials at a meeting last week that Mr Bo had been removed because of his involvement in the Wang Lijun affair. His comments were carried on Chongqing television.

Many might wonder, though, whether this is the whole story, as this version of events is convenient for a party that likes to show it plays by the book.

This narrative suggests Mr Bo's demise has more to do with wrongdoing than political manoeuvring at the top.

Meanwhile, it is unclear what has now happened to Mr Bo - and whether he is under investigation because of this alleged interference in the investigation into his family.