Long Island serial killer suspect charged with murdering former Clearwater resident

The announcement of the arrest of a suspected serial killer on Long Island, NY, on Friday hit close to home for a Clearwater woman who was a close friend of one of the victims.

In December 2010, Amber Lynn Costello's body was found near Gilgo Beach as police in New York searched for another missing woman. 

Nearly 1,200 miles away, Costello's friend, M'Rissa Rosenthal, was stunned.

"It's just tragic and horrible and just horrifying," said Rosenthal, who still lives in Clearwater.

 M'Rissa Rosenthal was friend's with murder victim Amber Costello when she lived in Clearwater.

M'Rissa Rosenthal was friend's with murder victim Amber Costello when she lived in Clearwater.

Rosenthal said Costello only lived in Clearwater for a few years but became close friends. Rosenthal was helping Costello battle drug addiction.

She wanted Costello to check in to a nearby drug rehab facility.

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"There was a bed available for her, and at the last minute, she bailed and changed her mind. And I just think, like, what if I had been more persuasive?" Rosenthal told FOX 13. "It's just heartbreaking because I always question, well, what if she had gotten the help she needed?"

Amber Costello

Amber Costello

Instead, Costello, 27, moved to New York a few months later. She was last seen in September 2010, and her body was found three months later. 

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She was one of four women whose bodies were discovered in a quarter-mile area days apart. They were dubbed "the Gilgo Four." All of them were sex workers.

Images of victims dubbed the Gilgo Beach Four.

Images of victims dubbed the Gilgo Beach Four.

By the end of 2011, detectives had found 11 victims, and police believed they were searching for a serial killer.

After 13 years, investigators announced Friday they'd arrested Rex Heuermann, an architect from Long Island, and charged him in three of the murders, including Costello's.

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"There's that sense of justice is being served, and somebody is being held accountable for their actions," said Rosenthal, adding she feels a little relief. "There's a lot of people that may not get that, and there are people that work tirelessly to bring justice to criminals."

Suspect Gilgo Beach serial killer Rex Heuermann with authorities.

Suspect Gilgo Beach serial killer Rex Heuermann with authorities. 

Investigators said they were led to Heuermann during a review of evidence that included a car registered to him at the time, cell phone and cell tower data, and DNA. Police said they executed over 300 subpoenas and were able to identify seven separate burner phones that he used.

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Heuermann pleaded not guilty to three counts of first and second-degree murder.

Rosenthal said she often thinks about her friend and wishes she could see her one more time.

"She was there for me when my grandfather passed away, so she was a superhero to me for that reason," she said. "I miss her a lot. She was a good friend."