Rex Heuermann, the suspected Gilgo Beach serial killer, has been charged with a seventh woman's death, according to prosecutors in New York's Suffolk County.
Valerie Mack, a 24-year-old from Philadelphia, went missing in 2000. Suffolk County police found her partial remains in Manorville, New York, after a group of hunters stumbled on a suspicious black bag that November.
The latest charges come as investigators continue to examine DNA evidence with state-of-the-art techniques that the defense plans to challenge, according to two sources familiar with the matter.
"Your honor, I am not guilty on any of these charges," Heuermann, wearing a dark suit with his hands shackled behind his back, told the judge Tuesday.
SERIAL KILLER SUSPECT REX HEUERMANN FACES MORE POSSIBLE CHARGES A YEAR AFTER ARREST
Police arrested the New York City architect outside his Manhattan office in July 2023, more than a decade after the search for a missing woman 45 miles east of Long Island's Gilgo Beach led to the discovery of 10 other bodies, including more of Mack's remains.
At first, investigators charged him with the murders of Melissa Barthelemy, 24, Megan Waterman, 22, and Amber Costello, 27. But a task force dedicated to solving all the deaths uncovered additional evidence.
Read the superseding indictment:
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In January, prosecutors charged Heuermann with the murder of Maureen Brainard-Barnes, 25.
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Then in June, a grand jury indicted Heuermann in connection with the murders of two more women: Jessica Taylor, 20, and Sandra Costilla, 28.
Suffolk District Attorney Ray Tierney, speaking to reporters after Heuermann's return to court Tuesday, said he doesn't believe they have any specific evidence with regard to the whereabouts of the suspect's family during the Mack murder. He had previously said evidence showed his wife and children were out of town during the other six murders.
Heuermann allegedly kept news articles and conducted internet searches regarding his victims, Tierney said.
When asked if the Gilgo Beach murder newspaper clippings found in Heuermann's basement were mementos, the DA replied, "I scored a touchdown in high school. I still have that article."
Like Taylor, Mack's dismembered remains were recovered in two separate locations, one along Ocean Parkway, near Gilgo Beach, and the other in Manorville, about 50 miles away.
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Police in at least three other states were also looking into unsolved cases for potential connections to Heuermann, Fox News Digital has previously reported.
Heuermann has pleaded not guilty to the prior charges. He is being held without bail at the Suffolk County Jail in Riverhead, New York.
According to prosecutors, the 60-year-old architect maintained a double life – a mild-mannered commuter with an office in Manhattan by day and a prolific abuser of sex workers in his downtime.
Investigators allegedly recovered his now-estranged wife's DNA at one of the crime scenes but say they believe it was transferred there by the killer.
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She and the rest of Heuermann's family were out of town for the murders, according to Suffolk County District Attorney Ray Tierney.
Heuermann's wife, Asa Ellerup, filed for divorce shortly after his arrest but has said she doesn't believe him capable of the accusations against him and would wait for the case to play out at trial.
Heuermann is due back in court on Jan. 15 for another hearing.
This is a breaking news story. Check back with Fox News Digital for updates.