CNN  — 

Since the spring of this year, investigators looking into the Gilgo Beach serial killings case have been operating on the theory that the suspect, Rex Heuermann, committed the killings in his Massapequa Park, New York, home.

A source involved in the investigation told CNN the fact that the disappearances occurred during times his family was out of town suggests he may have lured victims to the Long Island home.

Investigators believe committing the killings at home would have given Heuermann control of the environment and access to materials that were found at the crime scene, including tape and burlap bags, the source said.

One of the reasons the search of the suspect’s home has taken so long is because investigators are also combing for trace evidence that may be linked to the victims, multiple sources said.

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Heuermann was arrested in New York City last week and charged with murder in the deaths of three of the “Gilgo Four,” a group of four women whose remains were found along a short stretch of Long Island’s Gilgo Beach in 2010.

The 59-year-old architect has pleaded not guilty in the killings of Melissa Barthelemy, Megan Waterman and Amber Lynn Costello.

While in custody, Heuermann has shown “no emotions, whatsoever,” Suffolk County Sheriff Errol D. Toulon Jr. told CNN’s Erin Burnett Thursday night.

In a news conference last Friday, Suffolk County District Attorney Ray Tierney said Heuermann’s wife and children were both traveling when the killings were committed and the suspect was “alone in the tri-state area” during those times.

Heuermann is also the prime suspect in the 2007 disappearance and killing of the fourth victim, Maureen Brainard-Barnes, according to a bail application from prosecutors. He has yet to be charged in that homicide case but the investigation “is expected to be resolved soon,” the document says.

Women traveled to area of suspect’s home, police say

Barthelemy’s phone communicated with a burner cellphone several times before July 10, 2009, which was the last day she was seen alive, authorities said in Heuermann’s bail application.

On that day, cell tower records show the burner phone traveled from Massapequa Park to Midtown Manhattan and later that day, Barthelemy’s phone traveled from Midtown Manhattan to Massapequa, the application says.

Barthelemy’s last phone location was recorded in Massapequa on July 11, 2009, at roughly 1:43 a.m., the court document says.

Less than a year later, on June 6, 2010, Waterman was seen on surveillance footage leaving a hotel in the area of Hauppauge around 1:31 a.m., according to the bail application. It was the last time she was seen alive.

Waterman’s phone also communicated with a burner cell phone at around the same time she left her hotel, according to the bail application.

Cell tower records show her phone traveled to Massapequa Park, with its last location recorded in that area at around 3:11 a.m. “in the vicinity of the residence of” Heuermann, the bail application says. She was never seen alive again.

In the case of Costello’s killing, police say a burner phone contacted her the day before she vanished. In those communications, the burner phone connected to cell towers in West Amityville and Massapequa Park, the bail application says.

Around the time of the communications, witnesses said “a prostitution client” went to Costello’s residence, where a person pretended to be her “outraged boyfriend” as part of a ruse and got the client to leave, the application says.

The burner phone, which was located in Massapequa Park, messaged Costello’s phone early the next day, on September 2, 2010, saying, “That was not nice,” according to the document.

Later that day, Costello was again contacted by the burner phone, which was at Massapequa Park, the bail application says. That night, the burner phone traveled to the area of the woman’s house, according to the document.

On the night of September 2, Costello walked outside her home, leaving her phone behind, and was never seen alive again.

Police in other states are reviewing unsolved cases

As investigators in New York work to build their case against Heuermann, police in Las Vegas and South Carolina, where the suspect owned property, are reviewing their unsolved cases for any possible connection.

In Rock Hill, South Carolina, police are reviewing the disappearance of Aaliyah Bell, who was 18 when she went missing in November 2014, according to the National Center for Missing and Exploited Children.

“So far, there is no indication that leads us to identify Heuermann as a suspect in this case. We will continue to investigate Bell’s disappearance and follow up on all tips and leads,” Rock Hill Police Department spokesperson Lt. Michael Chavis said.

Nothing specifically prompted the review, Chavis noted. “This was a proactive approach after learning of Heuermann’s arrest and his ties to an area not far from us in South Carolina,” he said.

Rock Hill sits in York County, which borders Chester County, an area where Heuermann owns four large parcels of land, tax records show.

The sheriff’s office in Chester County said it has been gathering evidence for the Gilgo Beach investigative task force since before Heuermann’s arrest.

Late last week, authorities were seen towing a truck belonging to Heuermann’s brother, a neighbor who lives adjacent to Heuermann’s land told CNN.

In Las Vegas, where Heuermann and his wife purchased two timeshare condos, police said they are also reviewing their roster of unsolved cases for any possible connection.

The condos were purchased between 2003 and 2005, property records show. The couple has since sold the first property, the records show, and it is unclear whether they still own the second.

Strands of hair were key in the investigation

Strands of hair were among the key evidence that helped investigators bring Heuermann into custody.

In the initial examination of Waterman’s skeletal remains, investigators found a male hair from the “bottom of the burlap” the killer used to wrap her body, prosecutors said.

In addition, female hair now believed to be from Heuermann’s wife was found on or near three of the victims, prosecutors allege in the bail application.

But when they were found in 2010, the hairs were degraded, and DNA testing at the time couldn’t yield the results investigators hoped for.

It wasn’t until more than a decade later that improved technology offered answers.

Once authorities identified Heuermann as a suspect in early 2022 using cell phone data, witness descriptions and other information, they began watching him and his family, and collected DNA samples from items in their trash.

They got a complete sample of his DNA from leftover crust in a pizza box he discarded – and it matched the one from the male hair investigators had collected so many years ago, Tierney, the district attorney, has said.

Heuermann’s wife has now filed for divorce

Heuermann’s family was shocked, disgusted and embarrassed when authorities informed them of the crimes he is accused of, Suffolk County Police Commissioner Rodney Harrison told CNN’s Erica Hill on Monday.

“I don’t believe that they knew about this double life that Mr. Heuermann was living,” Harrison said.

On Wednesday – less than a week since Heuermann’s arrest – his wife, Asa Ellerup, filed for divorce, her attorney said. The two were married in April 1996 and lived since then in the suspect’s childhood home in Massapequa Park with their daughter and Heuermann’s stepson.

Ellerup “and her family are going through a devastating time in their lives,” a Thursday statement from her attorneys said. “The sensitive nature of her husband’s arrest is taking an emotional toll on the immediate and extended family, especially their elderly family members.”

“Ms. Ellerup does not wish to comment further and has requested the public and press to please respect the family’s privacy at this time.”

No one has visited Heuermann in jail other than his attorneys, Toulon said Thursday night.

This story has been updated with additional reporting.