Accused Gilgo Beach serial killer Rex Heuermann is being charged with a seventh murder: the November 2000 death of Valerie Mack, law enforcement sources told ABC News.

       Mack's remains were discovered in Manorville and Gilgo Beach. The New Jersey woman was identified through DNA. Like the other victims, prosecutors have said she was also involved in sex work.

       Mack’s parents are expected in court when Heuermann is arraigned on a new murder charge.

       Prosecutors named Heuermann a suspect in Mack’s death in June based on evidence allegedly found on an electronic device seized from Heuermann’s home in Massapequa Park on Long Island.

       Prosecutors have said Heuermann kept detailed notes about serial killings, body disposal and torture pornography.

       The architect and father has pleaded not guilty to charges stemming from the murders of six women whose remains were found in a remote spot along Ocean Parkway near Gilgo Beach and parts of eastern Long Island.

       Heuermann, 61, is scheduled to appear in court in Riverhead at 9:30 a.m. Tuesday.