Rex Heuermann pleaded guilty last week in a Riverhead courthouse to the murders of seven women and admitted to killing an eighth victim in the Gilgo Beach serial killer case that has haunted Long Island for over a decade.

The case breakthrough came through work by a Suffolk County police taskforce formed by former police commissioner Rodney Harrison, who was brought in from the New York Police Department where he had served as chief of detectives. The taskforce ultimately identified Heuermann as a suspect in the string of murders.

Heuermann, who worked as an architect, had interactions with privileged New Yorkers through his professional work while living in what has been described as a dilapidated house on Long Island. His dual life allowed him to move between different social circles while allegedly committing the murders.

The death of 23-year-old Shannan Gilbert, however, remains an unsolved mystery within the broader Gilgo Beach case. Her case continues to perplex investigators even as Heuermann's guilty plea resolves the murders of the other victims.

The Gilgo Beach murders have been one of New York's most notorious unsolved cases, with victims' remains discovered along Ocean Parkway on Long Island's South Shore over several years beginning in 2010.