According to court records unsealed Friday in Suffolk County Criminal Court, New York City architect Rex Heuermann is charged with the murders of Melissa Barthelemy, Megan Waterman, and Amber Costello. The bodies of the three victims were found wrapped in burlap along Ocean Parkway on Long Island's South Shore in December 2010.

Barthelemy disappeared in July 2009, Waterman in June 2010, and Costello was last seen in September 2010. All three women, aged between 22 and 27, were sex workers, according to court records.

"Rex Heuermann is a demon that walks among us," said Suffolk County Police Commissioner Rodney Harrison on Friday. "A predator that ruined families."

The court records revealed that shortly before each woman vanished, she had contact with a person using a burner cellphone with an unverified identity. The killer used the cellphones of two victims after their deaths.

During the summer of 2009, someone in midtown Manhattan, where Heuermann's office is located, used Barthelemy's phone to make taunting phone calls to her family members. Some of these calls led to conversations in which a male caller, admitting to killing and sexually assaulting Barthelemy, spoke with a relative of the victim, as per the documents.

According to court documents, Heuermann's wife was out of town when Barthelemy, Waterman, and Costello disappeared.

Maureen Brainard-Barnes, who went missing in July 2007, was also linked to the three women. While Heuermann is not charged in Brainard-Barnes' death, court documents identify him as the prime suspect. The investigation into her death is ongoing.

"Court documents state that the four victims were found in a similar position, bound with belts or tape," the records said.

Male hair found on the burlap used to wrap Waterman's body was found to match DNA from leftover pizza crust that Heuermann discarded in a Manhattan garbage can in January 2023, according to court documents.

Heuermann, a 59-year-old married father of two, used one of his burner phones to conduct thousands of searches related to sex workers, sadistic and torture-related pornography, and child pornography, according to court records. 

He also searched for information about active and known serial killers, as well as the disappearances of the Gilgo Beach victims. One search, as stated in the records, was "Why hasn't the Long Island serial killer been caught."

Heuermann also allegedly searched for and viewed photos of the Gilgo Beach victims and their relatives.

The suspect was arrested Thursday night in Manhattan, and law enforcement was seen outside his home in Massapequa Park on Long Island on Friday morning.

Heuermann first became a suspect in the investigation in March 2022, according to Suffolk County District Attorney Ray Tierney.

Heuermann was traced through his car, a Chevrolet Avalanche, which was discovered in 2022. A witness to Costello's disappearance reported seeing a Chevrolet Avalanche, court records revealed.

Detectives also tracked Heuermann through his cellphone records, according to the court documents. Cellphone mapping led investigators to focus on areas in Massapequa Park and midtown Manhattan, said Tierney.

Fears of a serial killer on the South Shore of Long Island began in 2010 with the discovery of a woman's body along Ocean Parkway. Over the next year, the bodies of seven more women, a man, and a toddler were found in the same general area.

Investigators have long believed that there could be more than one killer due to the different conditions in which the victims were found. The wooded stretches along Ocean Parkway have been known as dumping grounds for bodies.

Jasmine Robinson, a cousin of victim Jessica Taylor, expressed her shock at the arrest.

Taylor disappeared in 2003 at the age of 20. Partial remains were found in 2003, and additional remains were discovered in 2011 along Ocean Parkway.

"I hope that she's remembered as a beautiful young woman" and not as a sex worker, Robinson said on Friday.

Heuermann is charged with three counts of first-degree murder and three counts of second-degree murder.

Defense attorney Michael Brown entered a not guilty plea on Heuermann's behalf during his arraignment on Friday. Heuermann only spoke his name in court. He was ordered to be held without bail.

After the hearing, Heuermann's lawyer told reporters that Heuermann tearfully said, "I didn't do this."

"This is a good day," Harrison said at a news conference on Friday before embracing the victims' family members.

"There's more work to do in this investigation regarding the other victims of the Gilgo Beach bodies," he added, encouraging anyone with information to come forward.

ABC News' Mark Crudele contributed to this report.