whoever's doing this knows this area. they love the game. and this is a game to them. >> hundreds of tips, a swarm of media, multiple police jurisdiction, trying to catch a serial killer is complicated and highly confidential. but cnn's jason carroll was able to get some behind the scenes insight from one investigator who helped to catch the son of sam. that's a nickname david berkowits gave himself one summer. >> reporter: one former detective who helped find one of america's most infamous serial killers watches every development. >> this case is very wearing on detectives. and these guys out here, i feel for them because i went through the same thing with the son of sam. >> that's how he identified himself in 1977.