Gilgo Beach serial killer Rex Heuermann’s ex-wife says she now sleeps in the basement of their Long Island home, the same space where investigators say victims were killed and dismembered — a reality she says leaves her “haunted by dreams” each night, according to a documentary episode airing Thursday. Asa Ellerup moved into the stripped-down room after learning details of the crimes, including claims that several of the killings took place there. “The harsh reality is that Rex Heuermann said the bodies were dismembered in this room,” she said during an interview filmed in the space. #esaellerup #gilgobeach #rexheuermann