Bo Guagua, 25, who is studying in the US and has kept a low profile by avoiding to comment on the detention and trial of both his father and mother, in a statement to New York Times appealed to the Chinese government to allow his 64-year-old father to defend himself "without constraints of any kind".
Bo Guagua said that Bo's trial starting on August 22 would "carry no moral weight" if his father's consent to the charges or further cooperation from his mother Gu Kailai is sought bartering his safety.
"It has been 18 months since I have been denied contact with either my father or my mother. I can only surmise the conditions of their clandestine detention and the adversity they each endure in solitude," he said.
"I hope that in my father's upcoming trial, he is granted the opportunity to answer his critics and defend himself without constraints of any kind," Bo Guagua said.
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"However, if my well-being has been bartered for my father's acquiescence or my mother's further co-operation, then the verdict will clearly carry no moral weight," he said, sparking speculation that Gu is being persuaded to speak against her husband during the trial which would be held in Jinan in Shandong province.
There has been speculation that both the parents agreed to demands from Chinese officials in return for a guarantee that their son would not be pursued.
Bo Guagua also spoke out in defence of his mother, describing her as "silenced and defenceless", as he voiced concern over her state of health.
"She has already overcome unimaginable tribulation after the sudden collapse of her physical health in 2006 and subsequent seclusion," he said.