A French architect who was alleged to have links to scandal-hit Chinese politician Bo Xilai has left Cambodia for China, officials say.
Patrick Devillers was detained in the Cambodian capital Phnom Penh on June 13 at the request of China.
Devillers was reportedly to have had close links to Bo and his wife, Gu Kailai. He is said to have carried out work for Bo and had business ties with Gu.
The wife was arrested in China as a suspect in the death of British businessman Neil Heywood in November 2011.
Local officials initially said Heywood died of excessive drinking, but the government announced in April that it was investigating Bo's wife in connection with the case.
Both Heywood and Devillers are said to have been members of Gu's inner circle.
Officials say Devillers has left the country on his own free will.
"China wants him as a witness," Information Minister Khieu Kanharith told the Reuters news agency, adding that China had given an assurance that Devillers would only be required for up to 60 days before being allowed to return.
Devillers moved to Cambodia several years ago but previously lived in China, where he was close to Bo Xilai and Gu Kailai, according to people who knew him.
Bo's unknown whereabouts
Bo, the former leader of the south-western Chinese province of Chongqing, was sacked in March and is now under investigation for a string of accusations ranging from an abuse of power to flouting rules against the Communist party.
Al Jazeera's Stephanie Scawen said that the whereabouts of Bo was unknown.
"The only time the Chinese media have commented on the case was in April, when Xinhua revealed he was investigated for serious breach of communist party discipline and he was stripped of his post as Party secretary in Chongqing."
The Bo scandal, which first came to light in February, has exposed deep divisions within the Chinese Communist Party ahead of a crucial, once-in-a-decade leadership transition, analysts say.
Bo had been widely tipped for promotion to the top echelons of the Communist Party before the scandal spectacularly derailed his political career.
The French embassy in Beijing declined to comment on Devillers. China's foreign ministry could not immediately be reached for comment. Officials have yet to make any comment on his case.