Officers responded to the scene of the crash at about 3:30 a.m. in the area of the northbound 110 transition to the 101 Freeway.
It started when a South Pasadena police officer was responding to what appeared to be a disabled school bus stopped at an island between merging traffic lanes on the eastbound 10 Freeway. The bus driver told the officer he was stopped to render aid after he saw a downed motorcycle, but he was not able to locate the motorcyclist.
The South Pasadena officer then searched the brush along the freeway shoulder but was unable to locate the rider. While the officer spoke to the bus driver again, the officer saw a man get into the passenger's side of his patrol car.
The South Pasadena PD official ran toward his vehicle in an attempt to disable the car. Once inside, the officer and the suspect struggled over the wheel, and when the suspect put the car on drive, the officer backed off, according to South Pasadena PD Sgt. Spencer Lui.
The suspect ended up driving off before crashing into a tree in the area of the northbound 110 Freeway transition to the 101 Freeway. He was pronounced dead at the scene.
Police said it was not yet clear whether the suspect was the rider on the motorcycle.
The officer twisted an ankle when the patrol car was pulled away, Lui said.
Due to the collision, the 110 North transition road to the 101 Freeway was shut down until 7 a.m., according to the California Highway Patrol.