Authorities on Tuesday lined up along Bradford Avenue in Placentia near the scene of the first murder to ask drivers for their reason for traveling through the area.
"I actually think it's a great idea, and I'm glad they're making an effort, because usually they don't," said Maria Bupaz of Placentia.
The murders stretched from Placentia to Anaheim to Yorba Linda, but it was along Bradford Avenue that the suspect was captured on camera in a dark and grainy surveillance photo. Cameras also captured a white sedan that may belong to the killer or a possible witness.
Investigators passed out flyers and asked key questions.
"I think what makes this different is the contact with the driver. We're making face-to-face contact. Maybe someone has dismissed something in their mind as not important, but now, it might come out in conversation with an officer," said Sgt. Bob Dunn of the Anaheim Police Department.
While it meant a minor delay, drivers said it's well worth it, especially since detectives are trying to track down a man they say is a serial killer.
"I always thought this neighborhood, there's nothing too strange about it, but that is a little scary that they're calling it that," said Placentia resident Pam Myers.
Anyone with information was asked to contact police at (714) 765-1944.