Years after he was charged, Long Island serial killer Rex Heuermann changed his plea to guilty and admitted to the murders of eight women earlier this month. Katie Rosseinsky talks to the director behind a new series, unpicking a horrifying case that spanned several decades O n a bleak December day in 2010, a police officer named John Mallia took his dog, Blue, down to a desolate scrubland along the coast at Gilgo Beach in Long Island. Several months earlier, a young woman named Shannan Gilbert