Rex Heuermann.

gilgo beach serial killings

Since his arrest on July 13, authorities have been searching the 59-year-old architect’s Massapequa Park home on Long Island for evidence that may be related to the murders of at least three women, whose bodies were found along Gilgo Beach on Long Island in December 2010.

Suffolk County Police Commissioner Rodney Harrison tells PEOPLE that at the home, police have found several handguns, shotguns and rifles. But the investigation into Heuermann has now expanded into multiple states.

“He had a timeshare in Las Vegas,” the police commissioner tells PEOPLE. “And we’re working with the authorities out there to take a closer look at what needed to be recovered or if there’s anything that should be recovered and seized that could help out with this investigation as well.”

A spokesperson for the Las Vegas Metropolitan Police Department confirmed toCNNthat “police in Las Vegas are sifting through their roster of unsolved cases for any sign Heuermann may have been involved.”

Officials say Heuermann also has ties to Amityville and South Carolina. Meanwhile, Harrison says authorities have also been looking into similar unsolved murders in Atlantic City, N.J. that are possibly connected to the killings on Long Island.

“We’re trying to connect them to Mr. Heuermann,” Harrison tells PEOPLE, saying that the investigation is a “process” that “can’t be done overnight. So we’ll continue to get as much evidence as possible and try to get that [DNA] match.”

Heuermann was charged last week with three counts of first-degree murder and three counts of second-degree murder related to the deaths of Melissa Barthelemy, 24, Amber Costello, 27, and Megan Waterman, 22.

Maureen Brainard-Barnes; Melissa Barthelemy; Megan Waterman; Amber Lynn Costello.Suffolk County Police Department; Barthelemy family; Suffolk County Police Department (2)

Maureen Brainard-Barnes; Melissa Barthelemy; Megan Waterman; Amber Lynn Costello

Suffolk County Police Department; Barthelemy family; Suffolk County Police Department (2)

The father-of-two is also considered a prime suspect in the death of Maureen Brainard-Barnes, 25. All four women had worked as online escorts and had been missing between 2007 and 2010. Heuermann has pleaded not guilty to the charges he faces.

Investigators have since uncovered the remains of at least 10 people along Gilgo Beach, though they have said not all of them are believed to be connected to the same killer.

Suffolk County District Attorney Ray Tierney previously told PEOPLE that Heuermann was allegedly linked to the killings using cell tower data, a witness’s description of his Chevrolet Avalanche, and eventually, from DNA from five hairs found on three of the victims.

Harrison tells PEOPLE the alleged serial killer’s family was in “shock” and “disbelief,” following the news of his arrest.

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“We had to kind of show them some type of proof to let it be known who their father was behind the curtain,” the police commissioner says. “But they’re cooperating. They’re currently, I’m being told, in a hotel.”

Asa Ellerup, Heuermann’s wife, has since filed for divorce in Suffolk County Supreme Court, her attorney, Bob Macedonio, confirmed to PEOPLE on July 20.

Meanwhile, Harrison says he’s “very happy that we got [Heuermann] off the streets and we’re making this community safer.”

“[Heuermann] had no arrests, which also was very bizarre. Architect, had a good job, had a family, but suddenly we were able to put the pieces of the puzzle together, get in the right direction, be able to get to a point where we needed probable cause against Mr. Heuermann,” he tells PEOPLE. “And now he’s in a jail cell.”

source: people.com