Rex Heuermann: Soundproof Room Found in Basement of Gilgo Beach Serial Killer's Home as Police Suspect He May Have Killed Victim There

On Sunday, an investigator was seen outside the house carefully surveying the backyard with a sonar device that resembled a lawn mower, as shown in video footage.

Police searching the home of Gilgo Beach murder suspect Rex Heuermann reportedly found a soundproof room in a basement and think that at least one victim was killed there, it was revealed on Sunday. The horror discovery was made after cops used cadaver dogs and ground-penetrating sonar to search the backyard of Heuermann's home.

Police told a neighbor of the New York architect that they suspected the death of at least one woman in the room discovered during a significant excavation carried out by state troopers. Heuermann was arrested earlier this month and charged with the murders of three of the 'Gilgo Four,' a group of women whose bodies were found near Gilgo Beach on Long Island back in 2010.

Shocking Discovery

Rex Heuermann
Rex Heuermann Twitter

Robert Musto, 64, one of Heuermann's longtime neighbors in Massapequa, told the New York Post: "He's got a soundproof room in his basement. What do you think that was for?"

The retired Long Island Rail Road worker said "This guy is a wacko," asserting that he learned about the basement from the police, who have been investigating the area since Heuermann's arrest on July 13.

This comes after one of the former coworkers said that Heuermann, 59, the suspected serial murderer, once requested time off from his job as a Manhattan architect to construct a concrete-lined vault at his family's residence in Long Island.

Rex Heuermann
Drone footage shows law enforcement officials searching the backyard of Rex Heuermann's home Twitter

It remains unclear whether the basement compartment in question is the same one that police suspect may have been used as a killing chamber or if it is possibly the space previously mentioned to contain up to 300 guns belonging to Heuermann.

However, "it's not just a hidden room — it's a serious vault," the ex-colleague said. "It had a huge heavy-duty safe door. He went and poured new concrete walls, massive amount of concrete to encase this room.

"It was maybe 2 or 3 feet thick," the former coworker said.

Musto told the outlet: "They're saying there's evidence he killed at least one of the girls down there.

Rex Heuermann
Rex Heuermann Twitter

"The cops are going to dig all that out. Said they're focused on the soundproof room in the basement but they're going to look at everything."

Police told the outlet on Sunday that "cops are looking for evidence if the victims were in the house, nothing yet."

Mystery Continues

On Sunday, an investigator was seen outside the house carefully surveying the backyard with a sonar device that resembled a lawn mower, as shown in video footage. Additionally, three cadaver dogs were brought to the property, and state troopers referred to the operation as a "major excavation," as a backhoe and dump truck were also present at the scene.

The construction rig was brought onto the yard a little before 4 p.m.

According to local resident Kathy Huber, who claimed to have attended high school with Heuermann, the neighbors are understanding and accepting of the disruption caused by the ongoing investigation.

"We don't care how long this has to be here," Huber, 57, said Sunday. "This is a big community of cops and firemen, and I find it hard to believe that anybody here will be angry that cops are taking their time and doing a good job.

"With these girls, with these victims, please, take your time and get justice for these women and these families," she said, addressing authorities. "We don't care how long this has to be here."

Rex Heuermann
The moment cops in plain clothes pounce on an unsuspecting Rex Heuermann and arrest him Twitter

Law enforcement officials have been manually excavating Heuernmann's yard while also removing bags of items from the property and disassembling a wooden deck as part of their investigation.

In addition to the search at Heuernmann's property, the police have also conducted searches of two nearby storage units, looking for human remains or any other potential evidence related to the disturbing case.

Heuermann, a married father of two, was arrested outside his Midtown Manhattan office on July 13 and charged with the murders of Melissa Barthelemy, Megan Waterman, and Amber Lynn Costello. Their bodies were found in a marshy area in 2010.

Police suspect him to be connected to the death of Maureen Brainard-Barnes, completing the group known as the "Gilgo Four."

Rex Heuermann
Rex Heuermann is suspected of killing at least 10 people on Gilgo Beach more than a decade ago Twitter

Moreover, seven more bodies were found near the same location, which remains unsolved cases.

All four women linked to Heuermann worked as escorts.

Authorities have shared that the suspect was a regular patron of the sex trade.

Following Heuermann's arrest, the police conducted a search at his family home and seized numerous items, among which were a disturbing child-sized doll with blonde braids enclosed in glass and wood, a portrait of a disfigured woman, and a sizable collection of firearms—reportedly up to 300 guns, as indicated by law enforcement, photographs, and reports.

In addition to the vehicles previously seized, the police also impounded a Chevrolet Avalanche from the driveway and another one from a secluded property owned by Heuermann in South Carolina. It was the same model that eventually led to his capture.

Following his arrest, Heuermann's wife, who police said, is "disgusted" and embarrassed, filed for divorce last week. She has been in hiding despite being spotted a few times with her children and outside her lawyer's office.

During his court appearance, Heuermann pleaded not guilty to the charges. His lawyer has suggested that the police may have overlooked other "more significant" clues that could lead to different suspects.