(08-19) 19:56 PDT SANTA ROSA -- A 4-year-old boy died Friday after being struck in a Santa Rosa crosswalk by an unlicensed driver who was arrested after a witness saw him peeling off a large San Francisco Giants window decal off his car, police said.

The boy died at Children's Hospital Oakland, where he had been taken after Thursday evening's crash at West Ninth Street and Rockwell Place near Jacobs Park in Santa Rosa, said police Sgt. Lance Badger.

The boy, whose name has not been released, was crossing West Ninth with his twin sister, 6-year-old sister and their mother in a crosswalk and headed to the park for soccer practice when he was hit by a Honda Accord heading west on West Ninth at about 6 p.m., said police Sgt. Rich Celli.

There is no stop light or stop sign controlling cars approaching the crosswalk.

The car drove away. A short time later, Leroy Flach, 47, of Santa Rosa, who was listening to the police radio traffic about the hit-and-run, spotted the car at Finley Park, less than a mile from the crash, Celli said.

Flach said Friday that he figured that Finley Park would be a natural place for someone to dump a car because it has a large parking lot.

"Sure enough, there it was," Flach said.

He said he had seen the driver peeling off an orange San Francisco Giants decal from the rear window of the Honda. The man looked straight at Flach.

"I didn't want to spook him to where he would take off," Flach said. "That's when I pulled around where he couldn't see me and called police."The man got into a silver Volvo driven by a woman, said Flach, who gave police the license plate number.

At about 7:50 p.m., police found the suspect, Marcos Lopez Garcia, 22, of Santa Rosa, standing next to the Volvo outside an apartment on the 500 block of Sonoma Avenue, east of Highway 101. The woman was also there, and the descriptions of the pair matched those provided by Flach, Celli said.

"I wasn't trying to be a hero," Flach said. "I was just trying to help the family that might have just lost a kid."

Garcia, who lives near Jacobs Park, was arrested on suspicion of felony hit-and-run and was booked at Sonoma County Jail. Prosecutors could file more serious charges as a result of the boy's death.

He is being held without bail because federal officials suspect him of being an illegal immigrant.

Garcia does not have a driver's license and has two previous arrests for driving without a license. The most recent incident happened just five days before the crash, when he was told not to drive until a court appearance in October, Celli said.

The woman driving the Volvo in Thursday's incident was not arrested.