Paul Walker and his friend Roger Rodas were not racing another vehicle when they died after the Porsche Carrera GT they were in crashed and burst into flames, police have said.
Although speed is believed to have been a factor in the crash, accident investigators “have received eyewitness statements that the car involved was traveling alone at a high rate of speed,” the Los Angeles County Sheriff's Department said in a statement.
“No eyewitness has contacted the (department) to say there was a second vehicle.”
The announcement comes as fans of Paul Walker have been warned by police against “burning rubber” on the stretch of road where the Fast & Furious actor died, following reports that some drivers have been performing illegal stunts in tribute to him.
“We sent deputies to the accident location this morning after we started getting reports of drivers burning rubber and spinning tires at the site,” said Santa Clarita sheriff's office spokesman Richard Cohen.
“So far I haven't had any reports of any drivers being cited or arrested... But we have deputies there to stop that behavior if it happens again.”
The crash happened on a road that forms a loop through industrial office parks, which is a known hotspot for illegal street racers, California Highway Patrol Sgt. Rick Miler said. It is rimmed by hills and relatively isolated from traffic, especially on weekends when the businesses are closed.
Skid marks cover the route as testament to past activity. The sheriff's department, which polices the neighborhood, said Saturday's incident was not the first speed-related crash there, but would not reveal specifics.
Mr Rodas and Mr Walker had been on a 20 minute drive and were on the way back to an event hosted by the Fast & Furious star’s charity, when Mr Rodas seems to have lost control of the car.
Investigators are now consulting CCTV footage, talking to witnesses and analysing physical evidence including on-board computer data from the vehicle to try and establish the exact cause of the crash.
The bodies of Mr Rodas and Mr Walker have not yet been formally identified - they were so badly burned by the fire that dental records will be needed to confirm their identities.