Gilgo Beach investigators looking into unsolved murder cases nationwide to see if suspect is connected

Investigators are looking into unsolved murder cases nationwide for a possible connection with a Manhattan architect charged in the Gilgo Beach serial killings, authorities in Suffolk County, New York, said after it was discovered that he has ties to Las Vegas, Atlantic City in New Jersey and South Carolina.

Rex Heuermann, 59, was charged Friday with three counts of first-degree murder and three counts of second-degree murder in the deaths of Melissa Barthelemy, 24, Megan Waterman, 22, and Amber Lynn Costello, 27.

The remains of the women were all discovered in December 2010 in Gilgo Beach on Long Island’s South Shore, and they were all believed to have been sex workers who advertised on online sites, according to police.

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Gilgo Beach murders: Officials find suspect's car, two storage lockers

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Heuermann is also suspected in the disappearance and death of a fourth woman, Maureen Brainard-Barnes, 25, whose remains were also found near Gilgo Beach. That investigation remains ongoing, according to a bail application filed Friday.

A spokesperson for the Suffolk County Police Department said that among the cases being investigated are the deaths of four sex workers in Atlantic City in 2006. The spokesperson, however, noted that in the past, investigators have seen no connections between the killings and those in Gilgo Beach.

Atlantic City police directed questions to the county prosecutor's office, which said that the killings remain under investigation.

The Las Vegas Metropolitan Police Department said it was also "reviewing our unsolved cases to see if he has any involvement" and was aware of Heuermann's connection with the city.

It did not respond to an email Thursday seeking additional information. Two senior law enforcement officials told NBC News that Heuermann had a timeshare in Las Vegas.

In South Carolina, the Chester County Sheriff's Office said it had been asked by the Gilgo Beach task force to gather evidence related to the case. The FBI also conducted a court-authorized search on property in the area that belongs to a relative of Heuermann, an FBI spokesperson said.

Heuermann's Chevrolet Avalanche, a key piece of evidence in cracking the long-unsolved killings, was found at the property. A witness to Costello's disappearance had reported seeing an Avalanche. The vehicle has since been returned to Suffolk County for inspection.

The remains of the four women, known as the "Gilgo Four," were discovered during the search for missing Shannan Gilbert, 23, who was reportedly last seen running through the gated community of Oak Beach after leaving a client’s home, according to a police case timeline.

During the search for Gilbert, authorities found the remains of Jessica Taylor, Valerie Mack, 24, a female toddler and a man in Suffolk County. In neighboring Nassau County, where Heuermann lives, two additional sets of remains, of the mother of the toddler and an unidentified person, were found.

Gilbert’s remains were not found until December 2011.

Heuermann is not suspected in all of the deaths, but he was connected with Barthelemy, Waterman and Costello through cellphone data. DNA taken from discarded pizza also allegedly tied him to a male hair that was found on a burlap material used to wrap Waterman, investigators said.

Officials in New York said they are interviewing sex workers and trafficking victims who are currently or were previously in jail in Suffolk County for any other possible information.

Heuermann pleaded not guilty and has denied involvement in the killings. Michael J. Brown, an attorney for Heuermann, told reporters that the allegations are "extremely circumstantial in nature."

"The only thing he did say, as he was in tears, was ‘I didn’t do this,'" Brown said. "He’s distraught. He’s clearly distraught about the charges here."