Investigators obtained a cheek swab from Asa Ellerup the night her husband, Rex Heuermann, was arrested for the murders of three women whose remains were found wrapped in burlap in a marshy area near Gilgo Beach on Long Island.
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Prosecutors have said Ellerup's hairs were found on the burlap and now the sources said the DNA extracted from the hairs matches the cheek swab samples.
Prosecutors have cleared Ellerup of any wrongdoing and have said she was out of town at the time of the murders.
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Heuermann has pleaded not guilty to first and second degree murder charges in the deaths of Melissa Barthelemy, Amber Costello and Megan Waterman. He is the prime suspect in the killing of a fourth Gilgo Beach victim, Maureen Brainard Barnes.
The Suffolk County District Attorney's office has said DNA from Heuermann's cheek swab matched him to genetic material found on a pizza box investigators recovered from the trash near his Manhattan office.