In 1985, a massacre that became known as the White House Farm murders took place in Tolleshunt D'Arcy, Essex, with Jeremy Bamber convicted for the killings of his adoptive parents and his adoptive sister and her six-year-old twins. With previously unseen documents, fresh ballistic tests and testimony from those at the scene, this documentary raises new questions about Bamber's conviction - and whether crucial details, including a potential 999 call, could finally change everything