Fans of Fast & Furious star Paul Walker have created a makeshift memorial at the site where a car he was riding in crashed, killing the actor and a friend.

The Los Angeles County Sheriff’s Department says speed was a factor in the one-car crash in the community of Valencia, about 48km northwest of downtown Los Angeles. Deputies found a 2005 red Porsche Carrera GT engulfed in flames when they arrived on Saturday afternoon.

On Sunday, fans of Walker, 40, gathered to leave flowers, candles and memorabilia from the action film franchise.

Walker’s publicist said on Sunday that the other person in the car was Roger Rodas, a friend of Walker’s who owned a sport car dealership in Valencia.

Ame Van Iden said the actor was the passenger, though the sheriff’s department did not confirm that.

The Porsche crashed into a light pole and tree and burst into flames.

Sheriff’s deputy Peter Gomez said investigators are working to determine how fast the car was travelling and what caused it to go out of control, including whether the driver was distracted or something in the road prompted him to swerve.

Walker and Rodas had attended a fundraiser benefiting victims of the recent typhoon in the Philippines. The event was held by Walker’s Reach Out Worldwide, a charity he founded in 2010 to aid victims of natural disasters.

The fundraiser and toy drive took place at Rodas’ custom car shop, Always Evolving. Attendees rushed to the nearby crash to try to put out the flames with fire extinguishers.

Bill Townsend, who attended the event, told AP Radio that Walker appeared very happy at the fundraiser.

“He was smiling at everybody, just tickled that all these people came out to support this charity,” Townsend said.

“He was doing what he loved. He was surrounded by friends, surrounded by cars.”

The Fast & Furious star had been on break from shooting the seventh instalment of the Universal Pictures franchise. Production began in September and while much of the film has been shot, it’s incomplete.

Universal has not yet said what it plans to do with Fast & Furious 7, which is currently slated for release in July.

“Your humble spirit was felt from the start,” Ludacris, Walker’s Fast & Furious co-star, said on Twitter.

“Wherever you blessed your presence you always left a mark, we were like brothers.”

His Fast & Furious co-star Vin Diesel posted a photograph of him and Walker arm-in-arm on Instagram with the message: “Brother I will miss you very much. I am absolutely speechless.”

Walker rode the Fast & Furious franchise to stardom, starring in all but one of the six action blockbusters, beginning with the first film in 2001. The blond-haired, blue-eyed Los Angeles-native brought California surfer good-looks and an easy, warm charm to the popular street-racing series.

Walker is survived by his 15-year-old daughter.

He stars in the upcoming Hurricane Katrina drama Hours, which Lionsgate’s Pantelion Films is to release on December 13. He also stars in Brick Mansions, a remake of the French action film District B13 that Relativity plans to release next year.