The Gilgo Beach serial killer, Rex Heuermann, confessed to murdering all but one of his eight victims in their Long Island home, according to a teaser clip from the final episode of the Peacock doc “The Gilmore Beach Killer: House of Secrets.” The confession was made to ex-wife Asa Ellerup, who finalized her divorce from Heuemann last year. Despite being charged with seven murders prior to his April 8 guilty plea, Ellersup claimed that Heuemenn told her he killed eight women without hesitation, and that any victims were killed in his room downstairs. He also confessed to the murders of Amber Lynn Costello, Megan Waterman, 22, Melissa Barthelemy, 24; and Maureen Brainard-Barnes, 25, who were known as the "Gilgo Four."