Rex Heuermann, 59, is facing murder charges for the 2009 and 2010 deaths of the three women and is the "prime suspect" in the murder of a fourth woman, officials said.
"Rex Heuermann is a demon," Suffolk County police commissioner Rodney Harrison told reporters. "A predator that ruins families."
Heuermann, who lived in Massapequa Park, a town near Gilgo Beach, where the bodies were found, was arrested in Manhattan on Thursday evening.
All four women - Amber Costello, Melissa Barthelemy, Megan Waterman and Maureen Brainard-Barnes - were in their 20s and were sex workers, according to prosecutors.
"Each of the four victims were found similarly positioned, bound in a similar fashion by either belts or tape, with three of the victims found wrapped in a burlap-type material," U.S. District Attorney Ray Tierney said.
Tierney said the case against Heuermann was based on DNA evidence from a discarded pizza box, cellphone data linking him to the victims and a sighting of his vehicle at the home of one of the murdered women.
"For each of the murders he got an individual burner phone and used that to communicate with the victims," Tierney said. "Then, shortly after the death of the victims, he would get rid of the burner phone."
'Taunting calls'
Heuermann also performed hundreds of internet searches about the investigation into the murders, asking questions such as "Why hasn't the Long Island serial killer been caught?"
"In addition to that there was a lot of torture porn, and what you would consider depictions of women being abused, being raped and being killed" found on Heuermann's computer, Tierney said.
The U.S. attorney said Heuermann, who owned permits for 92 guns, also made "taunting calls" to a sister of one of the victims following her disappearance.
He said Heuermann's wife and children were always out of town when he allegedly committed the murders, which were the subject of a 2020 Netflix film called "Lost Girls."
The bodies of at least 11 people have been found since 2010 along the same isolated stretch of ocean beachfront on Long Island, but police have said previously they do not believe all of the cases are linked.
Heuermann is the owner of RH Consultants and Associates, which bills itself on its website as "New York City's premiere architectural firm."
Heuermann was interviewed last year for a YouTube show called "Bonjour Realty."
"I'm a troubleshooter, born and raised on Long Island, been working in Manhattan since 1987 - very long time," Heuermann said in the interview.