The chief administrator of Khon Kaen's Provincial Administration Organisation (PAO) was shot to death near his home on Friday morning.
Police said that Suchart Kothum, 53, had been shot once in the head and several times in the arms with a pistol. Officers found five bullet shells in front of his home on Kasikorn Tungsan Road in Muang district.
According to witnesses and the victim's family, Suchart had just driven past his house gate when a black pickup truck with three men inside blocked his way, said Pol Maj Gen Surapol Pinitchob, chief of provincial police region 4.
Two men came out of the pickup and talked with Suchart, who exited his vehicle minutes later. Gunshots were heard by people in the area and the attackers then fled.
The police suspect that there might have been a fight before the shooting and that Suchart tried to defend himself, given the wounds found on his arms. The motive might have been a personal or business dispute, they added.
Officers were continuing to investigate and were acquiring footage from CCTV cameras in areas around the crime scene, Pol Maj Gen Surapol added.