Bo's wife Gu Kailai, herself a celebrated lawyer, stands accused of murdering British business associate Neil Heywood -- a scandal that has rocked China's ruling Communist party ahead of a once-in-a-decade handover of power.

Chinese state media has said that Gu feared Heywood posed a threat to the safety of her 24-year-old son Bo Guagua.

In an email to CNN, Bo Guagua, who graduated from Harvard University's prestigious Kennedy School of Government earlier this year, said he had submitted a witness statement to his mother's defense team.

"As I was cited as a motivating factor for the crimes accused of my mother, I have already submitted my witness statement," he wrote. "I hope that my mother will have the opportunity to review them."

"I have faith that facts will speak for themselves," Bo Guagua said of the trial, which was scheduled to begin in the eastern Chinese city of Hefei on Thursday.

The CNN report, published late Tuesday, said Bo Guagua did not specify what he had written in his witness statement.

Heywood was found dead last November in his hotel room in the southwestern Chinese mega-city of Chongqing, where Bo was Communist Party leader until he was stripped of his post in March.

Bo had been seen as a top contender for a seat on the Politburo Standing Committee, the party's top decision-making body, until a top aide fled to a US consulate in February and accused Gu of involvement in Heywood's murder.

The move blew open a political scandal that has exposed deep rifts in the ruling party as the country's most senior officials prepare to give way to a new generation of leaders later this year.

Seven of the Politburo Standing Committee's nine members are due to step down as part of the handover.

Bo's political career has effectively been over since April when the party suspended him from his senior positions and placed him under investigation for violation of discipline -- usually code for corruption.

In April, Bo Guagua -- who had been criticized for partying and an allegedly extravagant lifestyle -- denied reports he drove a Ferrari and said his expensive overseas education was funded by scholarships and family savings.

"I am deeply concerned about the events surrounding my family," he said at the time in a statement to the Harvard Crimson, the university's newspaper.

"How could she be so gutsy as to kill a foreigner?" exclaimed one elderly woman in the eastern Chinese city of Hefei where Gu Kailai will on Thursday face trial for the murder of a British businessman.

"You can't kill someone over an economic dispute... it's too much."

The case of Bo, the ambitious and charismatic Chinese politician brought down by accusations his wife murdered a British businessman, has sent shockwaves through the ruling Communist party and made headlines around the world.

In Hefei though, it is having to compete with news of the Olympic Games and a recent heat wave, and half of those interviewed by AFP had not heard of the couple at the centre of China's biggest political scandal in decades.

Of those who had, there was a mixture of healthy scepticism about the fairness of China's courts -- which have a conviction rate of 98 percent -- and the sense that the relatively public nature of the trial would make it fair.

"If they say she's guilty, then she's guilty," said one man, who asked not to be named. "As ordinary people, we have no way to know if this will be fair."

Gu, a celebrated lawyer whose husband ran the megacity of Chongqing until he was sacked earlier this year, is accused of murdering a British businessman with whom the high-flying couple had business dealings.

The accusations first emerged earlier this year, sparking the biggest political scandal to hit China in decades as the country gears up for a generational handover of power that begins this autumn.

"Decades ago they would have resolved it among themselves," said a man surnamed Nu, 32, selling phone accessories on a busy street, of China's authorities.

"Now that they have brought it out into the open for ordinary people to see, they should make it a fair trial."

The hearing recalls one of the most high-profile trials in Chinese history, that of Mao Zedong's widow Jiang Qing, more than three decades ago.

Jiang and three others in the so-called "Gang of Four" were found guilty of excesses in the 1966-76 Cultural Revolution after the 1980 trial. Jiang was given a death sentence that was later commuted to life in prison.

The trial of Gu will, unusually for China, be attended by British diplomats. It is not known whether any media will be allowed to attend -- the Hefei court told AFP by telephone that "all seats are full".

China's state-run media have carried little coverage of the case against Gu, daughter of a revolutionary general, although some have touted it as evidence that no one is above the law.

Many residents supported holding the trial in Hefei, the capital of eastern Anhui province, to escape the power couple's sphere of influence.

But one young woman surnamed Guo said she expected Gu to get off lightly. "Officials protect one another," she told AFP. "They will do a backroom deal."

Any popular backlash would not have much bearing, said a 30-year-old businessman surnamed Chen, noting that many ordinary Chinese increasingly resented officials' families that acted like they were above the law.

"It doesn't matter," he said. "The government doesn't listen to us."