HERCULES, Calif. -- The driver of a car involved in an apparent street race Wednesday in Hercules that left a San Francisco sheriff's deputy dead has come forward to police Friday and is cooperating, a police spokeswoman said.

Hercules police spokeswoman Michelle Harrington, said the man, whom police are not identifying publicly, spoke with investigators this morning and has not been arrested.

San Francisco sheriff's Deputy Christopher Walker, 23, was killed after the red Chevrolet Camaro he was driving slammed into a light pole on Palm Avenue, between Sycamore Avenue and the state Highway 4 on-ramp, at about 2:30 p.m.

Walker, who was alone in the Camaro, was pronounced dead at the scene.

A witness reported seeing the Camaro and a silver car speeding down the roadway, according to Harrington.

The second driver's car, which left the scene of the crash, was described to police as a possibly a Nissan Sentra, but Harrington today said the car actually turned out to be a BMW.

Harrington would not release details about the man's statements to police, but said the incident is still believed to have been a street race.

"I don't think that's changed at this point," Harrington said.

"It does appear that both vehicles were involved in inappropriate behavior," she said earlier.

Harrington said the case remains an open investigation, and because the crash area can be seen from Highway 4, there may be other witnesses.

"The police would still like to talk with anyone who may have seen anything," she said.

Anyone with information is asked to call Hercules police at (510) 724-1111.

Walker, of Antioch, had worked at the sheriff's department for two years, most recently providing security at San Francisco General Hospital, according to spokeswoman Eileen Hirst. Before that, he worked at the San Francisco County Jail.

Hirst said Walker was a third-generation deputy sheriff, whose mother is a sheriff's lieutenant and grandfather was a former lieutenant.

Walker left behind "many friends in the sheriff's department," said Hirst. "He was a very well-liked deputy and a very good deputy," she said. His family is planning a private memorial service.