Accused Gilgo Beach Killer Rex Heuermann Charged With 7th Murder

Prosecutors are tagging alleged Gilgo Beach serial killer Rex Heuermann with another murder, saying his 7th victim is Valerie Mack.

Heuermann was arraigned Tuesday in the Suffolk County Courthouse in New York for the slaying of Mack, a former sex worker whose body was found in November 2000.

Prosecutors had named him a suspect in her death back in June ... based on evidence cops collected at Heuermann's Long Island home.

Cops say that evidence included detailed notes about serial killings -- and they also found DNA evidence linked to Heuermann near Mack's remains, which were uncovered on Gilgo Beach in 2010. Cops found Mack's skeletal remains 50 miles away, in Manorville, NY.

Heuermann has entered not guilty pleas in all the previous cases, and he did the same in the Mack slaying ... telling the judge today, "Your honor, I'm not guilty of any of these charges."

Law enforcement had found human remains from 11 different people between 1996 and 2011 -- but the reopened investigation didn't lead them to Heuermann until 2023, when he was arrested in July.