Surveillance video from a home in the Gramercy Park neighborhood of South Los Angeles shows a speeding silver Mazda violently slamming into a parked van early Friday morning.
As the car crashes, forcefully pushing the van forward, another dark-colored vehicle quickly drives past the collision.
Authorities said the 29-year-old man driving the Mazda appears to have lost control, swerved onto oncoming traffic and crashed shortly after midnight on Western Avenue near 93rd Street.
The driver became trapped in the vehicle and was severely injured, the Los Angeles Police Department said.
Firefighters freed the driver from the mangled car and transported him to a hospital where he was pronounced dead, according to police.
Police are looking for the driver of a black four-door sedan seen in the surveillance video as detectives work to determine whether the crash was a result of street racing, LAPD told KTLA.
Police did not identify the man killed in the crash, and no further details were immediately available.
Spencer Collins heard the crash and rushed to help.
"I heard a big boom, almost like an explosion," he told KTLA. "The whole passenger side of the car was completely demolished."
Collins said he checked the man's pulse as he spoke with an emergency dispatcher by phone.
Then, he did what he could to comfort the badly injured driver. "I wanted to make sure that he didn't die alone," Collins said.
"Whenever you see someone take their last breath, it’s devastating, whether you know them or not," he said.
The good Samaritan added that if the crash was the result of street racing, he hoped the other driver surrenders to authorities.