Winnie Johnson said in her final interview that she feared Moors Murderer Ian Brady would never reveal the whereabouts of her 12-year-old son's body in a "final sick twist".
The mother of Keith Bennett fought tirelessly for decades to find him and provide a Christian burial but Brady always refused to tell her where he buried him on Saddleworth Moor above Manchester.
She died peacefully in a hospice in the early hours of Saturday, aged 78, having suffered from cancer for a number of years.
Her family has now vowed to continue her campaign. Brady has been urged to "do the decent thing" and finally tell them where the body is so that Keith can be given a Christian burial.
The closest Winnie came to giving him 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."
In an interview with The Sun, conducted from her hospital bed, she had said: "I don't know now if Brady will ever tell me where my Keith is buried. He could take it to the grave with him. I suppose that would be his final sick twist. Or he could give me hope like he has done before and then nothing would come of it."
She added that it would make her feel "on top of the world" to know where her son's body was, and added: "It would mean my dying wish had come true and we had finally got Keith home. I don't give a s*** about Brady any more. I am running out of time and just want to bring my son home. But I feel in my heart he won't ever tell me."
Brady, 74, and his partner, Myra Hindley, who died in jail in 2002 aged 60, were responsible for the murders of five youngsters in the 1960s. Most of their victims were sexually tortured before being buried on Saddleworth Moor, with Keith's body the only one yet to be found.
Keith was snatched after he left home in Longsight on his way to his grandmother's house nearby on June 16 1964.
In a statement yesterday, Winnie's family said: "She was a much loved mother, grandmother and great-grandmother, and is survived by one younger brother. Winnie fought tirelessly for decades to find Keith and give him a Christian burial. Although this was not possible during her lifetime, we, her family, intend to continue this fight now for her and for Keith. We hope that the authorities and the public will support us in this."