Rex Heuermann allegedly killed at least three women found on Gilgo Beach along South Shore of Long Island
A suspected serial killer's sister-in-law said she was "stunned" and "this disbelief alone is profound and altering" after Rex Heuermann's arrest.
Heuermann, 59, is a married father of two and a Manhattan-based architect who allegedly killed three of the "Giglo Beach 4" victims. He's the prime suspect in the remaining woman's murder.
Dr. Johanna Ellerup, Heuermann's sister-in-law, seemed to put the blame on herself as she grappled with reality in an interview with NBC News.
"My ego has great difficulty processing the idea that I looked Rex in the eye and was unable to discern any murderous intentions," Ellerup said.
Rex Heuermann is led into Arthur M. Cromarty Criminal Complex in Riverhead for his arraignment on Friday, July 14, 2023. (Matt Agudo/Splash News for Fox News Digital )
"I vacillate between desperately wanting my niece and nephew’s life returned to its previous state, intact, without a father accused of being a serial killer to being pleased and secure in knowing that someone is in custody."
Less than a week after Heuermann's July 14 arrest, his wife, Asa Ellerup, filed for divorce.
Law enforcement across the country, including South Carolina, Las Vegas and Atlantic City, are scouring through unsolved missing persons cases and cold cases to determine whether Heuermann is involved.
As it stands now, Heuermann is accused of killing Melissa Barthelemy, 24, Megan Waterman, 22, and Amber Lynn Costello, 27, and is the prime suspect in Maureen Brainard-Barnes' murder
Gilgo Beach murders victims Amber Costello (top left), Maureen Brainard-Barnes (top right), Melissa Barthelemy (bottom left) and Megan Waterman (bottom right). (Suffolk County Police Department)
The four women became known as the "Gilgo Beach 4," and their puzzling murders were one part of this perplexing cold case.
Law enforcement found their bodies intact and wrapped in burlap near Gilgo Beach in December 2010 while they searched for a missing escort named Shannan Gilbert.
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Heuermann pleaded not guilty to six counts of murder (first- and second-degree murder for each victim). He hasn't been charged with Brainard-Barnes' murder as of July 22.
A skull mask mounted on a cross in the marsh behind Gilgo Beach, south of Long Island, New York on Wednesday, July 19, 2023. The remains of Megan Waterman, Amber Costello and Melissa Barthelemy were found on the beach in 2010. (Mega for Fox News Digital )
Between December 2010 and April 2011, law enforcement found dismembered remains of at least six other victims in the area.
Some of the victims' limbs were found in other areas of Long Island years earlier.
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The "Gilgo 4" were murdered between June 2007 and September 2010, but it took more than a decade and regime change in the Suffolk County, New York, District Attorney's Office to make an arrest.
Suffolk County District Attorney Ray Tierney created a task force when he took office in 2022 that included law enforcement from the local level to the FBI and investigators from his office.
Asa Ellerup and Victoria Heuermann walk through a parking lot. (Dario Alequin for Fox News Digital )
By March 2022, the task force identified Heuermann as a suspect, mainly from evidence already collected, like his Chevy Avalanche and cell phone data.
He allegedly used a burner phone to taunt Barthelemy's family, specifically her sister. The calls pinged in Midtown Manhattan, near the train heading to Long Island and on Long Island, according to court records.
Investigators watched his every movement for more than a year, got his DNA from discarded pizza crust and arrested him on July 14.
Heuermann is due back in court on Aug. 1 and faces up to life imprisonment without the possibility of parole if convicted.
Chris Eberhart is a crime and US news reporter for Fox News Digital. Email tips to
