Long Island Serial Killer Adept at Using Technology

There is a real limit to the technology used to catch criminals when the criminals know how it works.

A series of taunting phone calls made to the teenage sister of one of the victims — calls that the police suspect came from the killer — were made from in or around some of the most crowded locations in New York City, including Madison Square Garden and Times Square, according to the people briefed on the case and to the mother of Melissa Barthelemy, that victim.

The locations, detectives say, were probably chosen because they allowed the caller to blend into crowds, so that if investigators pinpointed his location from the cellphone’s signal, they would be unable to pick him out of the crowd using any nearby surveillance cameras, one of the people said.

This fact, as well as the killer’s use of disposable cellphones to contact the four victims who have been identified — women in their 20s who advertised their services on Craigslist — suggested to some investigators that the killer was well versed in criminal investigative techniques, gleaned either through personal experience or in some other way, and could even be in law enforcement himself.

“He is a guy who is aware of how we utilize technology,” one investigator said. “Frankly, people are thinking maybe he could be a cop” — either one still in law enforcement or one who has moved on. . . .

Also, the caller kept each of his vulgar, mocking and insulting calls to less than three minutes, according to the dead woman’s mother, Lynn Barthelemy. The caller made about a half-dozen calls over roughly five weeks to the victim’s sister.

One investigator said the brief duration of the calls thwarted efforts by the New York Police Department to use the signal to pinpoint the caller’s location and find him, something Lynn Barthelemy said they told her they tried to do four times. . . .