Cops are hunting a gunman who shot and killed a Houston security guard in his patrol car early Tuesday morning in an apparent ambush, police said.

No details about a suspect have been released.

The guard's patrol car was parked at a gas station in southwest Houston, KHOU reported.

Images from the scene appear to show the patrol car’s driver-side window shot out.

A security guard is typically posted overnight at the station when it’s closed, an area resident told ABC13. Tuesday's deadly incident occurred around 5 a.m.