A vehicle was fully engulfed in flames early Tuesday morning, but investigators do not yet know why.

Officers responded to the 500 block of 22nd Avenue Northwest around 4 a.m. Tuesday to a report of a vehicle on fire. Officers observed a 2004 Chevy Avalanche fully engulfed in flames. Two witnesses were working across the street and heard a loud banging or popping noise, found the back end of the vehicle on fire and called police.

The front passenger door was open when officers arrived. The Austin Fire Department arrived on scene and put out the fire.

An officer recalled passing the truck around 3 a.m. and noted nothing was wrong at the time. The Fire Department and Austin Police Department are investigating the incident.