Washington State Patrol Trooper Keith Leary said the crash happened about 9:45 p.m. Tuesday in the eastbound lanes of State Route 20 at Fidalgo Bay Road.
The 23-year-old motorcyclist was slowing down to avoid a collision ahead of him when he was hit from behind by another car.
The woman driving the car that hit him did not stop and sped away from the scene, Leary said. The impact from the crash knocked the motorcyclist off his bike and into the road, where he was hit by another car. Leary said the driver of that vehicle did stop.
The motorcyclist, identified as Michael J. McCurdy, was airlifted to Harborview Medical Center in Seattle where he died early Wednesday.
The license plate from the car that first hit McCurdy was ripped off by the impact and was found at the crash scene, Leary said. Troopers spotted the car a short time later as it was being towed down a road in Anacortes.
Asked why she left the scene without reporting the crash, the driver told troopers that she was scared, according to Leary.
The woman, identified as 26-year-old Gisela Carmona-Moreno, was booked into the Skagit County Jail for investigation of hit-and-run and is being held on $100,000 bail.