A 35-year-old man died Thursday night in North County after crashing into the back of a car, a driver told The California Highway Patrol.
A 43-year-old woman in a Volkswagen Passat said she was driving east on State Route 78 when she saw two "high-speed" motorcycles in her rear view mirror, speeding up to her car.
As she tried to move out of the fast lane, she felt one of the motorcycles slam into the rear of her car, according to the CHP.
The motorcyclist, a 35-year-old man from Oceanside, flew off his 2000 Kawasaki Ninja and onto the freeway. He was pronounced dead at the scene.
The CHP says the other motorcyclist did not stop, and investigators are not sure if that person played a role in the fatal collision.
The driver of the Passat was not injured.
The CHP closed down three eastbound lanes on State Route 78 after the crash, issuing a Sig Alert at El Camino Real.
Drugs or alcohol do not appear to be factors in this collision, and it is still under investigation.