Pol Capt Wutthisak Poonsawat was killed behind the house of his mother-in-law in Tambon Sakor in Sungai Padi at 8am.
Wutthisak, a deputy inspector of Sakor police, went to the house to take care of his fighting cocks before going to work at the police station.
Witnesses said three men in black came out of a wood beside the house and one of them shot at Wutthisak five times with an M16 assault rifle before the three fled into an adjacent rubber plantation. Five spent M16 shells were found at the scene.