Rex Heuermann pleads guilty in court on Wednesday in Riverhead, New York. Photo: James Carbone/Getty Images Rex Heuermann , the suspect in the decades-old Gilgo Beach murders , has pleaded guilty to the seven killings charged against him, a marked shift after long maintaining his innocence in the alleged crimes since his arrest nearly three years prior. He also confessed to an eighth killing of a woman who had not previously been associated with him. During a scheduled appearance in Suffolk