LOS ANGELES (AP) — Investigators sought to determine the cause of a fiery crash that killed “Fast & Furious” star Paul Walker while the actor’s fans erected a makeshift memorial Sunday near where the Porsche he was riding in smashed into a light pole and tree.

The Los Angeles County Sheriff ’s Department said speed was a factor in Saturday’s one-car crash, though it will take time to determine how fast the car was going.

Because Walker is so closely associated with the underground culture of street racing portrayed in the popular “Fast & Furious” film franchise, the fatal accident had an eerie quality — a tragic end for a Hollywood hero of speed.

The crash also killed Walker’s friend and financial adviser Roger Rodas, according to Walker’s publicist, Ame Van Iden. She said Walker was a passenger in the 2005 red Porsche Carrera GT when they drove away from a fundraiser in the community of Valencia, about 30 miles northwest of downtown Los Angeles.

Sheriff ’s deputies found the car engulfed in flames when they arrived at the site of the crash, near the fundraiser at Rodas’ sport car dealership. Officials have not identified either person found in the car.