Cambodian Foreign Minister Hor Namhong was quoted by the BBC as saying that Patrick Devillers, 52, the French man held in connection with Bo's case would not be sent to China or France.
Devillers was arrested on June 13 upon China's request, Camboadiabn police said after his detention.
The French man reportedly had close links with Bo and his wife, Gu Kailai, besides British businessman, Neil Heywood, who was allegedly poisoned to death by Gu.
She along with an orderly was arrested in connection with Heywood murder case. Heywood was found dead in a hotel in Chongqing in November 2011.
Bo, former Chief of China's flourishing Chongqing's city has been stripped of all his positions in the party and being investigated for indiscipline.
Cambodian officials said they needed more evidence before they could consider Devillers' extradition.
It remains unclear where he is being held, the BBC report said.
"The decision has been made. We have decided to keep him here, we are not sending (him) anywhere. We won't send him to either France or China," Hor Namhong said.
A spokesman from the Cambodian foreign ministry also said no evidence was presented to prove that Devillers had committed a crime.
Officials had previously said that they were considering whether to send Devillers, who has been living in Cambodia for the past five years, to China or France.
