The victims of a truck fire early Sunday morning believe the culprit may have been arson, not electrical as was initially suggested by the Austin Police Department.

James Watkins, the brother-in-law of the truck owner, said the vehicle was parked outside his house, 1010 Seventh Ave. N.E., when the fire occurred around 5 a.m.

He said Tuesday that he found a burnt water bottle filled with gasoline in the backseat of the car, which he believes was thrown through the driver’s side back window allegedly broken by the suspect.

Austin Police Chief Paul Philipp confirmed Wednesday that officer Todd Clennon visited the home this week and found a “mostly-burned” water bottle that smelled of gasoline.

He and Fire Chief Dan Wilson said the matter is still under investigation.

According to the police report, the Watkins had been sleeping before they noticed smoke coming from the 1999 Ford Ranger truck. Police officers tried and failed to smother flames using an extinguisher; the firefighters ultimately put out the fire.

The Ford belongs to Victor Celestino Aguilar of Austin.