The mother of Moors Murders victim Keith Bennett has died without knowing where her son is buried.
Winnie Johnson, 78, had been suffering from cancer for a number of years and passed away peacefully at a hospice earlier today, her lawyer said.
The search for the remains of one of Ian Brady and Myra Hindley's victims has led detectives to south west Wales.
49-year-old Jackie Powell, who is Brady's mental health advocate, has been arrested on suspicion of preventing the burial of a body.
It's alleged Brady handed her a letter detailing where Keith Bennett is buried. His remains have never been found.
A spokesperson for Dyfed Powys Police said the force is 'co-operating' with Greater Manchester Police following the arrest of a 49-year-old woman in South Wales.
The woman, who is reported to be an advocate for Ian Brady, was arrested on suspicion of preventing the burial of a body without lawful exercise.
She has since been bailed.
A Greater Manchester Police spokesperson says officers are investigating the possibility that Moors murderer Ian Brady has revealed in a letter the location of one of his victims - but added it could be 'a ruse'.
Martin Bottomley, from Greater Manchester Police's Major and Cold Case Crime Unit, also stressed that Brady has not revealed the location of 12-year-old Keith Bennett's body to police.
– Martin Bottomley, Greater Manchester Police
I want to be explicitly clear about this: Ian Brady has not revealed to police the location of Keith's body. What we are looking at is the possibility, and at this stage it is only a possibility, that he has written a letter to Keith's mum Winnie Johnson, which was not to be opened until after his death. We do not know if this is true or simply a ruse but we clearly have a duty to investigate such information on behalf of Keith's family.
A 49-year-old woman has been arrested in South Wales on suspicion of preventing the burial of a body without lawful exercise.
A woman arrested and bailed in South Wales on suspicion of preventing the burial of a body without lawful exercise has been named as Ian Brady's advocate Jackie Powell by Press Association sources.
Jackie Powell is reported to have told a television production company that Brady gave her a letter to give to Winnie Johnson, the mother of his 12-year-old victim Keith Bennett, in the event of his own death.
Powell has reportedly told Sky News that her words have been 'misrepresented' and 'blown out of all proportion'.
Sky News also reports that Powell contacted police herself.