NEW YORK (CBSNewYork) — You hear it all the time from the neighbors and friends of an alleged criminal.

“He was such a nice, quiet guy.”

It was definitely the case for a Long Island landscaper-turned serial killer, but how do they get away with it for so long living among us?

Joel Rifkin referred to his propensity to kill as “almost an addiction,” something forensic psychologist N.G. Berrill says makes a certain amount of sense.

Berrill spent hours with the convicted killer, talking with him on behalf of the defense team.

“He was thoughtful, he was relatively well-spoken,” Berrill said. “He had some sense of humor, he seemed to appreciate the fix he was in.”

The fix started 25 years ago, this past summer, when state troopers caught up with Rifkin after he crashed his pickup truck on the Southern State Parkway.

Officers at the scene made a grisly discovery.

“He was caught with a body that was decomposing,” Berrill said.

The body was that of a prostitute, one of 17 Rifkin admitted to strangling over the course of four years.

“Had he been more streetwise, things might have gone differently,” Berrill said.

The killer grew up a suburban kid, and by all accounts wasn’t a criminal until his very first murder.

“That’s what makes these guys so scary, they don’t come off as raving lunatics,” Berrill said. “They don’t come off as deeply disturbed.”

In a recent interview with CNN, Rifkin said he thought by killing just one woman he would have gotten it out of his system.

“There was a lot of self lying,” Rifkin said.

Ultimately, it was actually his own self-loathing that drove him to kill.

“Dating back to Jack the Ripper, he fits the patterns,” Berrill said. “Antipathy for other people, particularly prostitutes… that they feel are beneath them.”

It’s that overwhelming sense of anger and despair that turned Rifkin into the type of “lay in wait” serial killer we don’t often see on the loose today.

Berrill says that’s since been supplanted by mass shooting incidents.

In 2011, CBS2’s Mary Calvi questioned Rifkin about his potential involvement in the murders of more than a dozen additional prostitutes whose bodies were found buried along Ocean Parkway. That time, the convicted killer said he couldn’t take the credit.

Calvi asked Rifkin if he would kill again if he was let out of prison.

‘I would like to say no, but honestly… yes,” he replied. It’s something she said has stayed with her for years.

Rifkin is serving life in prison.