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Sister-in-law of suspect in Gilgo Beach murders 'stunned' and in 'profound' disbelief

"This disbelief alone is profound and altering," said the sister-in-law of Rex Heuermann, who was charged last week in three murders.
Authorities remove evidence as they search the home of suspect Rex Heuermann on July 18, 2023, in Massapequa Park, N.Y.
Authorities remove evidence Tuesday as they search the home of suspect Rex Heuermann in Massapequa Park, N.Y. John Minchillo / AP

The sister-in-law of the New York architect charged in a series of killings on Long Island said Friday that she was "stunned" and in "profound" disbelief following his arrest in the killing of three women more than a decade ago.

Rex Heuermann, 59, was charged last week 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.

Dr. Johanna Ellerup, Heuermann's sister-in-law, said in an email to NBC News on Friday that she is "stunned" and "this disbelief alone is profound and altering."

The suspect was arrested last week at his home in a quiet neighborhood in suburban Massapequa Park. He has a wife and two adult children. 

"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," Ellerup said. "My ego has great difficulty processing the idea that I looked Rex in the eye and was unable to discern any murderous intentions."

She added that her half-sister "is going through a uniquely difficult time."

She declined to speak further in consideration of her family and said she does not have additional knowledge of the case. 

Heuermann’s wife, Asa Ellerup, filed for divorce Wednesday, her lawyer said. Attorney Robert Macedonio said a summons and a complaint had been filed on behalf of Asa Ellerup in Suffolk County Supreme Court.

Ellerup and her family "are going through a devastating time in their lives," Macedonio said in a statement to NBC News on Friday afternoon.

"The sensitive nature of her husband’s arrest is taking an emotional toll on the immediate and extended family, especially their elderly family members."

Authorities have said Ellerup was out of state at the time of the killings and isn’t considered a suspect.

The Suffolk County Police commissioner said this week that Heuermann’s family was shocked when they learned of the allegations against him. 

"They were disgusted. They were embarrassed," Suffolk County Police Commissioner Rodney Harrison told CNN on Monday. "So, if you ask me, I don’t believe they knew about this double life that Heuermann was living."

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 on July 14.

The victims were all believed to have been sex workers who advertised on online sites, according to police.

Rex Heuermann is charged with the slayings of Melissa Barthelemy, 24, left, Megan Waterman, 22, second from right, and Amber Lynn Costello, 27, right. Heuermann is suspect in the disappearance and death of Maureen Brainard-Barnes, 25, second from left.
From left, Melissa Barthelemy, Maureen Brainard-Barnes, Megan Waterman and Amber Lynn Costello. Suffolk County Police Department via AP file

The victims, known as the “Gilgo Four,” were discovered during the search for another missing woman, Shannan Gilbert, 23, who was last seen running through the nearby gated community of Oak Beach after having left a client’s home, according to a police timeline

The police would end up discovering the remains of more than 10 people.

Now, investigators say they are looking into unsolved murder cases nationwide for a possible connection to Heuermann, according to authorities in Suffolk County, after it was discovered that he has ties to Las Vegas, South Carolina and Atlantic City, New Jersey.