At about 11:50 p.m., an officer attempted to stop a motorcyclist on Second Street near Holmes Street for speeding. The motorcyclist immediately accelerated away and turned south onto Holmes Street, according to police.
He ran a red light at Holmes and Fourth streets, and the bike struck the driver's-side fender of a Ford minivan traveling east on Fourth Street, police said.
The motorcyclist was pronounced dead at the scene.
The driver of the minivan suffered minor injuries and was treated at ValleyCare Medical Center and released, police said.
The motorcyclist's name is being withheld pending notification of next of kin, police said.
Police noted that Holmes Street is marked as a 35 mph roadway. The motorcyclist was wearing a helmet, but was not licensed to ride a motorcycle. It is unknown whether drugs or alcohol played a role in the crash, police said.
The intersection was closed until about 4:30 a.m. today, police said.
The fatal motorcycle crash was the city's second this year, according to police. There have been four fatal vehicle crashes total.
Anyone with information about the incident is asked to call the Livermore Police Department's traffic unit at (925) 371-4850.