Passers-by spotted the body of Krailas Chokchaipol, 45, in Wat Wang Ma in Tambon Wang Mueang at 9.30pm.
The village headman had attended a funeral at the temple, police said. He was killed inside his pickup truck. The pickup had traces of five shotgun bullets, four of which hit Krailas in the back.
Krailas used to work as a bodyguard for an election candidate seeking the CEO position in the Nakhon Sawan Provincial Administrative Organisation. The candidate had previously been fatally shot and died in hospital several years ago.