Long-Buried Secrets: The Serial Killer and the Detective

The inmate made it clear that pressure would not work. “‘Don’t think you’re going to mess with me and I’m going to help you,’” Mr. Anzilotti recalled Mr. Cottingham saying.

The sergeant was undeterred. He tried a different approach. Over the months that followed, Mr. Anzilotti cultivated an unusual relationship with Mr. Cottingham, sometimes testy, sometimes closer to a sort of warmth. Mr. Anzilotti would arrange to have the inmate transported to his office more than hour’s drive from the prison. He’d order pizza and play cards with the older man and other detectives. Then he’d clear the room until only he and Mr. Cottingham faced each another, and begin with his questions. He had his list of names, each one a dead girl and a crime long unsolved.

The little perks for the older man — the pizza, the poker, the distraction from prison life — were always in the service of the younger man’s long game. Eventually, Mr. Cottingham began to loosen up, and he spoke about killing the prostitutes. “Which, of course, I wasn’t overly interested in,” the former chief said. Those cases were already closed. “But it was a way to get him comfortable to talk to me about murders.”

These meetings went on for months, and then years, on top of Mr. Anzilotti’s regular caseload. Mr. Cottingham had a vulnerability, the chief realized: After divulging nothing during hours of questioning, he’d sometimes loosen up on the drive back to prison, sitting in the back seat and believing the day was done.

“He would let his guard down,” Mr. Anzilotti said. The killer would suddenly recall picking a girl up from a store somewhere, and the chief, in the front passenger seat as a detective drove, surreptitiously took notes.

After six years of visits, there was a break.

“He said, ‘I’m going to give you one,’” Mr. Anzilotti recalled.

Sitting in a conference room, Mr. Cottingham calmly reached back more than 40 years and described how he’d murdered a woman whose name he couldn’t remember, a 29-year-old mother found strangled in her car in Ridgefield Park, N.J., in 1967. He described things only the killer would know, like where he’d thrown her car keys afterward.