The body of Sok Dam, 49, was found buried in a shallow grave Friday in Kompong Chhnang province after disappearing since 24 February, 2004.
There were two blood stained bamboo clubs nearby the body. Police is investigating.
Sok Dam was a member of the Sam Rainsy Party (SRP) Boribo District Council.
An SRP spokesman said Sok Dam is very friendly and did not seem to have any enemy. He is survived by his wife and two daughters.