A TV documentary about Moors murderer Ian Brady will air tonight with the approval of Winnie Johnson's family, broadcaster Channel 4 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.
In a statement, Channel 4 said: "This documentary will be airing tonight as planned following consultation with Winnie Johnson's family and with their approval.
"There will be tweaks to reflect Winnie's sad passing but otherwise the film will remain unchanged."
The closest Mrs Johnson came to giving Keith a funeral was to hold a memorial service at Manchester Cathedral two years ago in which she tearfully told the congregation: "I'm Keith's mother... he's there on the Moors, I want him back."
Keith's brother, Alan Bennett, said yesterday that the death of their mother must not be seen as closure to the case and vowed to continue the fight to locate the remains of the 12-year-old.
Writing on his website, www.searchingforkeith.com, Mr Bennett, who was nine when his brother was taken, said: "As far as I am concerned, until Keith is found then he is still in the possession of Brady and Hindley."