Across Cambodia, detentions without probable cause are a common occurrence and a concern to rights groups, a leading rights investigator said Thursday.

People can be jailed for political affiliations, for personal grudges, for mistaken identities, and relatively few safeguards are implemented to prevent extended detention of the innocent.

Suspects often lose their rights when they are arrested, said Chan Saveth, a leading rights investigator for the independent group Adhoc. This includes the rights to a lawyer, access to family members and other visitors and medical treatment.

Torture and confession under duress are also common, Chan Saveth said, as a guest on "Hello VOA."

A recent case of mistreatment could be found in the death of Oum Chhay, the suspected drug trafficking who fell to his death earlier this week, Chan Saveth said.

Oum Chhay was a key suspect and witness in a case against drugs production in Cambodia, but fell from a high building where he was being questioned, reportedly while his guards—three of them—were gone using the toilet.

Rights investigators for Adhoc and other groups, as well as journalists, were not permitted to verify his cause of death, Adhoc has said.

It was unclear if Oum Chhay was mistreated after his arrest earlier this month.