It could be weeks before investigators can conclusively determine the cause of the Saturday car crash that killed "Fast and Furious" actor Paul Walker and Roger Rodas, the star's friend and business partner, according to source at the Los Angeles Sheriff's Department.

On Monday, the Department announced that while it was continuing to solicit information about the fiery crash that killed Rodas, who is believed to have been driving, and Walker, it had received "eyewitness statements that the car involved was traveling alone at a high rate of speed. No eyewitness has contacted the Los Angeles County Sheriff's Department to say there was a second vehicle. The posted speed limit in the area is 45 mph."

Fans of the 40-year-old actor have assembled an ad hoc memorial of flowers, photos and candles at the site where he and Rodas died in the 2005 Porsche Carrera GT that was able to reach 205 mph.

The fate of the seventh installment of the "Fast and Furious" movie which Walker was in the midst of filming is still unclear. But the Hurricane Katrina drama, "Hours," starring Walker will be released as planned on Dec. 13, according to press reports.