GREENSBURG — State Police say a trooper who was killed when his cruiser collided with a garbage truck in July was at fault in the wreck, which also injured his partner and passenger.

State police say the cruiser’s speed — which isn’t being revealed — as well as wet conditions and fog contributed to the crash that killed Trooper Michael Stewart, 26, on July 14. Trooper Travis November suffered a concussion.

The crash happened about 2:20 a.m. on Route 711 in Ligonier Township.