LOS ANGELES - A police officer trying to find the rider of a motorcycle abandoned in a freeway traffic lane had his police car stolen by a man who jumped inside, raced away and almost immediately crashed the vehicle into a tree, killing himself.

"These type of things when you see them on movies or TV shows or something (you think) it can't possibly happen," police Chief Arthur Miller told reporters later. "But when you involve human nature, anything is possible."

South Pasadena police said the bizarre set of events began before dawn Thursday when an officer returning from delivering a prisoner to Los Angeles saw a school bus parked at about 3:30 a.m. on a downtown median where two major freeways merge.

"The officer contacted the bus driver, who told him he had come across a downed motorcycle in traffic lanes," police said in a statement.

After the bus driver said he had moved the abandoned motorcycle off the traffic lanes, the officer searched nearby brush, looking for an injured motorcycle driver.

Finding no one, he had returned to the bus and then saw a man walking toward his patrol car.

Police said the officer assumed at first that the man might be the motorcyclist seeking help. Then he saw him enter the police cruiser through the passenger door, climb over its centre console and drive away.

Miller said the officer managed to get partially inside his car and was trying to disable it when it picked up speed.

"Once he felt that he was being drug under the car he excited the car, got out of the car and then let the car go," Miller said.

He was treated at a hospital for minor injuries. His name was not released.

The police cruiser vehicle travelled a short distance before it rammed into a tree, and police said they found the driver dead inside. The impact reduced the vehicle to a crumpled heap, its windshield shattered. The subsequent police investigation backed up morning rush-hour traffic into downtown for miles in several directions.

Police said they don't know if the car thief was also the motorcycle rider.

Officials said the victim's name would be released by the county coroner's office, which did not immediately respond to a message left Thursday.

News from © The Associated Press, 2016