Suffolk County Police Commissioner Rodney Harrison told a news conference on Friday: “Rex Heuermann is a demon that walks among us – a predator that ruined families.”

The suspect, who was arrested at his home on Thursday night, is facing three counts of first-degree murder and three counts of second-degree murder in the three women’s deaths. The judge in the case ordered that he remain in custody, citing the “extreme depravity” of the crimes.

The lawyer, Michael Brown, said his client was “distraught” and called the evidence “extremely circumstantial”.

“We’re looking forward to fighting this case in a court of law, not the court of public opinion,” Mr Brown said.

Ms Barthelemy, Ms Waterman and Ms Costello were found dead in 2010 near a fourth victim, Maureen Brainard-Barnes.

The women have been dubbed the Gilgo Beach Four. All were sex workers, according to prosecutors.

Suffolk County District Attorney Ray Tierney told Friday’s news conference that “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”.

The local prosecutor said the case against Mr Heuermann was built on mobile phone records linking him to the victims, as well as to a pick-up truck that was seen near one of the victim’s homes. He allegedly communicated with the victims using “burner” phones, which he later disposed of.

Phone records also allowed investigators to determine that the deaths had taken place when Mr Heuermann’s wife and children were out of town.

Hair found on a piece of burlap used to wrap one of the victims was linked to Mr Heuermann via a sample from a pizza box he discarded in a rubbish bin in Manhattan in January 2023, according to authorities.

Investigators say he was also snared by taunting calls that a person claiming to be the murderer made to one of Ms Barthelemy’s family members using her mobile phone.

Ms Barthelemy was abducted in 2009. Ms Waterman and Ms Costello both went missing in 2010.

Mr Heuermann is also a prime suspect in the death of Ms Brainard-Barnes, who was abducted in 2007, although he has so far not been charged with her death.

In 2010, police were searching for one missing woman, Shannan Gilbert, when they discovered the remains of four others.

Altogether, 11 sets of human remains were found on the same stretch of Gilgo Beach between 2010-11, linked to nine women, one man and a toddler. The identities of four, including the toddler, her mother and the man, remain unidentified.

Ms Gilbert’s remains were eventually found, and an official post-mortem examination was inconclusive. Her family believes she may have been murdered – a theory supported by an independent autopsy that they commissioned.

A new task force to investigate the Gilgo Beach murders was formed in February 2022. Mr Heuermann became the focus of the investigation within a month, Mr Tierney said. More than 300 subpoenas and search warrants were issued by investigators on the case.

Since the task force was formed, Mr Heuermann allegedly also used a burner phone to conduct more than 200 searches about topics related to serial killers and the Long Island investigation.

This included a search for “why hasn’t the Long Island serial killer been caught” and “mapping the Long Island murder victims”, court documents show.

Mr Tierney added that “torture porn” and “depictions of women being abused and being killed” were found on Mr Heuermann’s computer.

The investigation into the other victims is ongoing.

Mr Heuermann is the owner of RH Consultants and Associates, a Manhattan architecture firm that describes itself as “New York City’s premier architectural firm”.

The Associated Press has reported that he has a daughter and a stepson. A neighbour described the 6ft 4in suspect going to work every morning, dressed in a suit and tie and carrying a briefcase.

Mr Tierney said that Mr Heuermann had licences for 92 guns and a “very large safe” in which firearms were kept.

In a YouTube interview for a real estate-focused channel last year, he said he had been working in the heart of New York City since 1987, describing himself as a “trouble shooter”. He added that his work helped teach him to “understand people”.

People who lived near his home in Long Island’s Massapequa Park expressed surprise at his arrest.

“The guy’s been quiet, never really bothers anybody,” neighbour Etienne DeVilliers told CBS, the BBC’s US partner.

“We’re shocked. Because this is a very, very quiet neighbourhood. Everybody knows each other, all of our neighbours, we’re all friendly.”