Police in Tempe say it may have been illegal drug production that caused an explosion inside an SUV last night.

The blast, which took place outside a convenience store, blew out the rear window of the vehicle.

Store employees helped the driver out the fire the explosion triggered, but by the time first-responders arrived, the driver and the vehicle were gone.

The SUV was located in a nearby apartment complex parking lot, but the driver remains at large. Officers with the bomb squad checked the vehicle and say it did not contain explosives.

But a police lieutenant told reporters it appears a torch was used to extract hash oil from marijuana and the resulting fumes ignited inside the vehicle.