Arnie Corlin is driving the streets of Watts, police radio blaring.
Just days before, a man had been shot to death nearby in his white Pontiac. Corlin navigates narrow roads with one-story homes and drives past churches and boarded-up markets, on the hunt for the next best thing to a witness to the killing: surveillance cameras.
Corlin, 57, doesn't have a badge. He's an LAPD volunteer and self-professed "gadget guy" who has aided in dozens of homicide investigations by tracking down and downloading surveillance footage that may have captured a crime.
A stout man who talks fast, Corlin heads down East 92nd Street in his car and spots a two-story duplex with a camera on the side. His brown eyes squint to see the numbers, and he pulls over to log the address.
Even if the camera didn't catch the crime, it might have caught parts of the story.
"I'm keeping an open mind," Corlin says.