Los Angeles County Sheriff’s officials are investigating a variety of potential causes of the car crash that killed actor Paul Walker and race car driver Roger Rodas in Valencia on Saturday, including the possibility that they may have been street racing, authorities said Monday.

Investigators received a call Saturday night from someone who said “they believe (Rodas and Walker) may have been racing another vehicle” but that information has not been verified or corroborated by anyone else, Sgt. Richard Cohen of the Santa Clarita Valley Station said Monday.

“We have not been able to confirm that,” Cohen said. “We have not been able to contact that person.”

Rodas, 38, and Walker, 40, were in a 2005 red Porsche Carrera GT on Saturday afternoon when Rodas lost control of the supercar on a street in an industrial park in Valencia. The car hit a tree, slammed into a light pole, then hit another tree and caught on fire just before 3:30 p.m. Saturday, Cohen said. Sheriff’s officials believe the car was going faster than the 45 mph speed limit at the time, he said, but they haven’t determined a specific speed.

While speed is believed to have been a factor, there are “a million possibilities” as to the cause of the crash ranging from an animal crossing the road to an automobile malfunction, Cohen said.

“We don’t know at this point,” he said. “The investigation is ongoing and going full force.”

Investigators are hoping to obtain any video from witnesses that may provide some clues, he said.

As of Sunday night, coroner’s officials had yet to positively identify the badly burned bodies though witnesses and those who knew the pair identified them Saturday.

Brandon Torp, 28, of Santa Clarita, who knew Rodas and attended Walker’s charity event Saturday at the Always Evolving custom car shop, said Walker wanted Rodas to take him for a ride around the block since he had never ridden in Rodas’ Porsche.

Torp said he watched them leave from the parking lot, and was one of the first people on the scene of the crash and tried to put out the flames with a fire extinguisher.

Torp said it was unlikely that Rodas would be racing since he cherished his car so much that he wouldn’t risk getting it impounded, causing damage to the car or injuring anyone.

“I know he wouldn’t risk anything happening to the car or getting into an accident racing somebody,” he said. “It was literally a drive around the block.”