Cambodian authorities on Tuesday acknowledged they had arrested Patrick Devillers, but declined to say why. On Wednesday, government spokesman Khieu Kanharith said China had requested Devillers' arrest because of possible involvement in the murder in China last November of British businessman Neil Heywood.
Kanharith gave no details of Devillers' alleged involvement, however, and said Cambodia was studying whether to extradite him.
Heywood had close ties to Bo Xilai, a Chinese political high-flier who was ousted as Communist Party chief of the Chinese city of Chongqing. But those ties had soured and Heywood's death led to the end of Bo's career.
Bo's fall came after his former police chief and longtime aide fled to a U.S. consulate and divulged suspicions that Bo's wife, Gu Kailai, was involved in Heywood's death. Bo was removed as Chongqing party secretary on March 15 and was suspended as a Politburo member amid questions over whether he tried to quash an investigation of his wife and a household employee over the Briton's death.
Though authorities in China initially said Heywood died from either excess drinking or a heart attack, they have since named Gu as a suspect. She faces criminal charges.
News reports have said that Devillers was closely linked to Bo, Gu and Heywood.
Khieu Sopheak, a spokesman for Cambodia's Interior Ministry, also said China had asked Cambodia to arrest Devillers for possible involvement in Heywood's death.
But he said China must give more evidence before Cambodia will extradite him.
"We need more evidence, clear information from China, before we are going to make a decision," Khieu Sopheak said. "If there is no clear evidence from China, Devillers will be set free."
He said Cambodia could hold Devillers for up to 60 days before deciding whether to extradite him.
Eric Bosc, deputy to the French Foreign Ministry spokesman, said Tuesday that Devillers was arrested June 13 and that the reason remains unclear.
Kanharith said Devillers was living openly in Cambodia and was not in hiding. Devillers, an architect, had helped Bo rebuild the northeastern Chinese city of Dalian when Bo was the city's mayor in the 1990s, The New York Times reported last month.
The Frenchman and Gu were partners in setting up a company in Britain in 2000 to select European architects for Chinese projects and both gave the same address of an apartment in the English city of Bournemouth, the newspaper said.
It cited an unidentified friend of Devillers as saying the architect left China in 2005 and has been living in Cambodia more or less continuously for about six years.
China has considerable influence in Cambodia, having provided millions of dollars in aid over the past decade.
In 2009, Cambodia deported 20 members of the Uighur ethnic minority group who said they were fleeing ethnic violence in China's far west and wanted asylum.