A TV documentary about Moors murderer Ian Brady will air tonight with the approval of Winnie Johnson's family, Channel 4 has confirmed.
Mrs Johnson, 78, whose son Keith Bennett was killed by Brady and Myra Hindley in 1964, died on Saturday without ever finding out where the 12-year-old was buried.
Her death came just hours after it emerged that police are investigating whether a letter exists in which Brady, 74, apparently discloses the location of Keith's body.
Brady's mental health advocate, Jackie Powell, told the documentary that Brady gave her a sealed envelope containing a letter to pass to Mrs Johnson in the event of his death.
That information was passed to police and Ms Powell, 49, was arrested on Thursday at her home in Llangennech, South Wales, on suspicion of preventing the burial of a body without lawful exercise.