A Sam Rainsy Party activist and two of his relatives were shot and wounded in the legs Tuesday night in Battambang province.
Local police initially said it's an robbery attempt but said it's investigating.
The Sam Rainsy Party calls the shooting politically motivated because it says the SRP activist had a quarrel with his neighbor, who is a member of the Cambodian People's Party.
The SRP also disagrees with the police who called it a robbery because the victim's motocycle is very old.
Human Rights organizations are also looking into the incident. The Cambodian People's Party does not have any comment on the shooting at this point.