Gustavo Guido was too angry after his van was rear-ended to be afraid of the other driver, who ran off with Guido chasing him.
He caught him, but, in retrospect, he may have second thoughts about the chase.
That's because police told him the man he grabbed is accused of shooting two motorists in a carjacking just up the block from where the chase began.
"I didn't realize he was armed," Guido said in an interview Monday.
Jose Luis Martinez, 20, of Palmdale, was arrested at the scene and police will ask prosecutors Wednesday to charge him with felony offenses ranging from carjacking to attempted murder, Los Angeles Police Detective Mel Arnold said.
Martinez pulled a driver out of a 1978 Datsun 280Z, which was stopped at a red light at Coldwater Canyon Boulevard and Vanowen Street early Sunday morning, and shot him in the head with a pistol, Arnold said.
The driver, Sabino Bernal, 23, of Van Nuys, was listed in serious condition at a local hospital Monday.
Martinez continued shooting as Bernal attempted to make his way to a nearby restaurant, and a stray bullet struck the arm of a passing motorist, who was not seriously wounded, Arnold said.
Martinez then fled south on Coldwater Canyon Boulevard in the stolen Datsun and west on Victory Boulevard, rear-ending Guido's van, which was halted at Fulton Avenue, Arnold said.
Guido said after Martinez fled, he caught up with him as Martinez tried to scale a fence leading to a residential back yard.
"I told the guy 'What's going on with you? Couldn't you see the red light?' " Guido said. "He was all nervous and he was shaking."
Guido said Martinez agreed to return to the crash scene only after Guido agreed to let Martinez call a tow truck to unhook their fenders. But when police arrived, Guido said, he was shuffling through the glove compartment of the Datsun, looking for the registration, and the officers mistook him for Martinez, who was at a pay phone calling for a tow truck.
Thinking he was a fleeing carjacker, they made him lie on the ground while they questioned him, Guido said.
After police got the situation straightened out they arrested Martinez instead, Arnold said.
Police searched Martinez for a gun but found none and came up with nothing in a search of the nearby area, Guido said.
Even worse than being mistaken for a carjack suspect, said Guido, was the estimated $2,000 in damage to his van.
"I'm just very depressed at what happened," he said. Even though he is an auto body worker himself, the van needs parts and "I don't have any money of my own to fix it," he said.