The spectacular fall from grace of Chinese Communist Party leader Bo Xilai has triggered a riveting political scandal seeped in twists and turns worthy of a Hollywood thriller or detective novel.

Bo's sacking as head of the Chongqing megacity, his purge from the powerful Politburo and the revelation that his wife is a suspect in the alleged murder of a Briton feed into what has become China's biggest political scandal in decades.

"Bo will be the first member of the Political bureau (Politburo) since the founding of the People's Republic of China to potentially be implicated in a murder," said Hu Xingdou, professor at the Beijing Institute of Technology.

His is a story of betrayal, hunger for power and money which remains shrouded in plenty of mystery while the rumour mill goes into overdrive, particularly on foreign Chinese websites not blocked by the nation's censors.

The scandal combines all necessary ingredients for a blockbuster -- a rising political star who sees his huge ambitions brutally cut short and his wife investigated over the murder of a foreigner who may have been poisoned.

It also throws China's Communist elite into the spotlight, hinting at a gilded life lived beyond the law.

And six months ahead of an important party congress, it is a huge embarrassment for the current Communist leaders who live hidden behind the high walls of Zhongnanhai in Beijing and are normally used to more discretion.

"This is all very significant with regards to the state of China today, where money and power are inextricably linked," said Michel Bonnin, a Beijing-based China expert, adding the scandal was a "first" in modern China.

The saga has also taken on an international dimension with Neil Heywood, the British businessman whose death in Chongqing in November is being investigated as murder. Authorities say Bo's wife Gu Kailai may have been involved.

To add to this, the scandal only burst into the open in February when Bo's right-hand man Wang Lijun fled in apparent panic to a US consulate, reportedly demanded asylum and handed over large amounts of information about his former boss.

China's tightly controlled traditional media have only published official information about the case, but behind this facade of unity, rumours, comments and questions are swirling.

For instance, how exactly did Heywood die? People close to him cited by British newspaper The Times say the theory that he had drunk too much alcohol does not stand up, as he was never a heavy drinker.

The Hong Kong-based Mingjing website, quoting party sources, alleges that an official in Chongqing admitted to police that he had provided one of Bo's men with potassium cyanide to get rid of Heywood.

But authorities are going to have a hard time proving anything, as the Briton's body was quickly cremated, rendering it impossible for experts to conduct an autopsy.

Another question is who wanted Heywood dead? Bo's wife, a successful lawyer and businesswoman, has been named as a prime suspect.

The official Xinhua news agency revealed on Tuesday that Gu Kailai and her son Bo Guagua "had conflict (with Heywood) over economic interests, which had been intensified."

According to the Wall Street Journal, Gu had been investigated for corruption in 2007, after which she grew increasingly neurotic and suffered from depression.

The report says that Heywood had started feeling threatened by the Bo clan, which was putting him under "intolerable pressure."

Some Chinese websites based in the United States, such as Renminbao.com or Boxun.com, even talk about a potential affair between the Briton -- who was married to a Chinese woman -- and Bo's wife.

Finally, who was Neil Heywood? A close business associate of Bo and his family, he occasionally worked for an intelligence company reportedly staffed by former employees of British spy agency MI6.

Whatever the answers, the scandal is likely to haunt the ruling Communist Party for months, and could sour the run-up to a congress this autumn that will kick start a key leadership change, which Bo could before have been part of.

"The world of princelings (sons of revolutionary heroes like Bo) is a completely surreal one. Since their childhood, they have been used to being above the law," said Bonnin.

Bo is currently being investigated by the Communist Party for "serious discipline violations" and if he is found guilty, he will be kicked out of the party altogether and probably brought before the courts.

His fate will then depend on the outcome of political infighting between the party's reformist and conservative clans.

If his wife Gu is found to be implicated in Heywood's murder, she will be put on trial and jailed.

"She could even be sentenced to death if she is the instigator of the murder of a foreigner," said Bonnin, adding that the sentence would probably be commuted to life in prison.