Officers were called to Maryland Avenue near 45th Avenue just before 7 a.m. Tuesday after a neighbor reported seeing an unresponsive man in a parked car with the engine running.
Police say 72-year-old Mark Leroy Woodruff was found sitting in the driver's seat of his vehicle in the driveway of his home and had a gunshot wound.
Glendale firefighters declared him dead at the scene.
Police say Woodruff worked as a night custodian at a Phoenix church and it's believed he was killed when he returned home early Tuesday.
Police say no suspects have been identified yet and they're looking for leads in the case.