Two agents from the US Federal Bureau of

Investigation arrived in Phnom Penh this week to assist in the

investigation of the murder of opposition journalist Khim Sambo and his

son, a US embassy official has confirmed.

US embassy spokesman John Johnson said the agents arrived on Sunday,

following a request from the Ministry of Interior, and that their role

would be "purely supportive" of the Cambodian investigation.

Johnson said the agents have no definite timeframe for their involvement and could stay until the investigation is complete.

Phnom Penh's Deputy Police Chief Hy Prou, who is heading the

investigation, said his police officials met with the agents Wednesday

to discuss the case.

He said police currently have no leads on a suspect and that the complexities of the case have made investigation difficult.

But Chan Soveth, a program officer with the Cambodian rights group

Adhoc, expressed concern that the FBI was not taking a more aggressive

role in the investigation.

"If the FBI cannot work independently, [their assistance] is just a political game," he said.

Chan Soveth arrived at the scene of the July 11 double homicide about

30 minutes after it occurred and has been investigating the killings

ever since.

According to Chan Soveth's recently completed preliminary assessment,

Khim Sambo's reporting for the Sam Rainsy-affiliated  newspaper Moneak-

sekar Khmer had frequently prompted threats from powerful individuals.

Contradicting claims made by some government officials, Chan Soveth

said he found no evidence that either Khim Sambo or his son were

involved in a personal dispute that could have triggered the killings.

IF THE FBI CANNOT

WORK INDEPENDENTLY [THEIR ASSISTANCE] IS

JUST A POLITICAL GAME.

Khim Sambo was killed instantly after being shot twice in the

back while riding on a motorbike driven by his son, Chan Soveth said.

His son was also shot twice from behind and died later that night in a Phnom Penh hospital.

"The perpetrators had no fear of being arrested. They weren't wearing

helmets and made no attempt to disguise their identity," he said.

Chan Soveth said he was able to gather information from those present during the crime after he arrived at the scene.

When he returned the next morning, no one would speak to him.

Chan Soveth declined to say who he believed was responsible for the killings.

"I want to continue living in Cambodia," he said.

ADDITIONAL REPORTING BY CHEANG SOKHA