A Red Bluff, Calif., police officer was shot and killed execution-style at a gas station in the rural town while he filled his patrol car.

Officer Dave Mobilio, 31, a four-year veteran of the Red Bluff Police Department, was killed early Tuesday morning, according to Tehama County Undersheriff Dennis Garton. The county sheriff's department, police department, and state officials are investigating the shooting. There were no witnesses, but investigators want to question a man in his mid-20s who may have been in the area around the time of the shooting. Garton says there hasn't been a police officer shot in the rural county in his 22 years with the sheriff's department. Police say they have no reason to believe the shooting is connected to any of Mobilio's past cases. Mobilio leaves behind a wife and a young child.