12/04/2013 01:11 EST | Updated 02/03/2014 05:59 EST

Paul Walker died of 'traumatic and thermal injuries' from crash

Actor Paul Walker, star of the Fast and Furious film series, died of the "combined effects of traumatic and thermal injuries" in last weekend's car crash, the Los Angeles coroner announced today.

Los Angeles County coroner officials confirmed the 40-year-old and his friend, Roger Rodas, died in the Valencia, Calif., crash on Saturday, after their vehicle smashed into a light pole and tree before exploding into flames.

Walker, who was the passenger in the Porsche Carrera GT, died of the "combined effects of traumatic and thermal injuries," while driver Rodas died of "multiple traumatic injuries," the autopsy report says.

On Monday night, a private memorial for survivors and the cast and crew of the Fast and Furious movies was held inside a white tent erected around the crash site in Valencia. When it was over, Walker's co-star, Vin Diesel, emerged to thank fans for paying their respects to the actor.

Investigators are still probing what exactly caused Rodas's car to lose control, and have said speed was a factor.

Walker starred in all but one of the six Fast and Furious films, which had been set to release a fresh instalment in July. Since his death, producers have halted production on the upcoming release.

More to come