The brother of Moors Murders victim John Kilbride has said that Ian Brady should be "kept alive until he tells where Keith Bennett's body is".
Speaking to BBC Radio 5 Live, Terry Kilbride said: "If he does take it to the grave it's gonna be a real sad ending for the Bennett family".
Moors murderer Ian Brady will give evidence to his mental health tribunal on Tuesday.
Brady has brought the mental health tribunal, which is being held in public, because he believes he is not mentally ill and wants to be transferred to a prison.
The 75 year old, who has been on hunger strike since 1999, believes he will be able to starve himself to death in a jail.
Currently he is assessed as being chronically mentally ill and is fed through a tube in his nose.
Judge Robert Atherton, who chairs the three-man panel hearing the tribunal, said, "We are going to take Mr Brady's evidence on Tuesday ... He will probably be the last witness".
Moors murderer Ian Brady remains "chronically psychotic" and should remain in a hospital setting for treatment, his mental health tribunal was told today.
The child killer suffers from long-term paranoid schizophrenia which does not "just fade away and die", according to the clinician in charge of his care at high security Ashworth Hospital in Merseyside.
Brady, 75, was constantly paranoid about the Home Office and the Prison Officers Association, and believed hospital staff were acting as their agents, a panel sitting at the hospital was told.
Giving evidence, Dr James Collins said Brady also had paranoid beliefs about fellow patients who he thought were spying on him.
Ian Brady has addressed his tribunal to explain, for the benefit of the media, why he left his hearing this morning.
But he has been rebuked by the judge chairing the panel for suggesting that Ashworth Hospital's lawyer was "wasting time".
Judge Robert Atherton had explained via video link that Brady was allowed to leave to relieve himself of stress.
But Brady, in his weak, low voice, explained: "It wasn't because of stress. It's because the Ashworth evidence is just repetition. It's already been repeated endlessly. I've listened to it ad nauseam and I know it by heart.
"That counsel [pointing with his finger at Eleanor Gray QC] is repeating herself."
Judge Atherton responded forcefully: "The tribunal will conduct this tribunal. If we take the view that somebody is wasting time then they will be told. But we have two Queen's Counsel doing their job absolutely properly. Thank you."
Brady continued to mutter but the tribunal proceeded to the next witness, Dr Collins, giving evidence for Ashworth Hospital.
Ian Brady is occupying himself making notes on a document passed to him by his solicitor.
He passes the paper close to his eyes while reading, and makes his notes laboriously with his right hand.
All the while the nasogastric tube taped beneath his right nostril dangles loose.
Occasionally he sits back and his white shirt stretches across his torso. His build does not appear to be skeletal, despite a hunger strike which stretches back fourteen years.
Ian Brady has appeared on the video link from his tribunal hearing for the first time since leaving the room this morning.
Earlier Judge Robert Atherton explained that Brady was free to come and go from the proceedings, and was not forced to attend.
Just after 3.15pm the camera showed him seated beside his solicitor wearing a long black coat, black jacket, a white shirt and a thin black tie. He continued to wear 'aviator' type dark glasses with gold-coloured rims. In spite of the hot weather he also appeared to be wearing a black woollen scarf.
Brady was shown blowing his nose on a paper tissue, before sitting back with his arms folded. Earlier the sound feed from the tribunal room featured a series of four explosive sneezes. It was not possible to determine whether the sneezes came from Brady.
If he were not serving a long prison term, he should be given a "conditional discharge" from hospital, argues his medical witness.
But if he returns to prison, he would almost certainly engage in dispute. Questioned by panel chair Judge Robert Atherton, he observed: "If he engages in conflicts and disputes, that keeps him going," says Grounds. "He finds it rewarding".
Ian Brady's transfer from hospital to prison would probably lead to conflict with prison authorities, targetting by fellow inmates, and a search for ways to end his own life, his medical witness has admitted.
Dr Adrian Grounds was questioned by Dr Cameron Boyd, a member of the tribunal panel.
Asked what the result of a transfer to jail would be, Dr Grounds said: "For a while [Brady] would be relatively settled, it would be a relief for him, he would be cooperative and observant.
"But over time, it's possible some issue would arise, he'd want something which wasn't available, and that would lead to conflict and intransigence".
Asked about his reported intention to end his own life in prison, Dr Grounds said of Brady: "He wishes to have control over the manner and timing of his death. He would be looking for means of achieving it. The risk of self-harm is real".
And pressed on whether Brady would be at greater personal risk in a prison, as a potential target for violence, Dr Grounds said: "These are everyday problems in the prison service. They don't require a hospital to manage them".
Ian Brady will not be giving evidence at his mental health tribunal before Monday, panel chair Robert Atherton said.
He also explained that Brady is allowed to come and go from the tribunal as he pleases - the Moors murderer briefly left the room this morning.
Dr Adrian Grounds, Ian Brady's medical witness, said the Moors murderer has told him he "doesn't mind the prospect of living in restricted, confined circumstances".
He also refers to Brady's disciplinary record during his 19 years in jail - which preceded his transfer to Ashworth - and suggests it was not "indiscipline...but an engagement in a series of battles".
Dr Grounds suggests that these "battles" resulted from the official refusal to allow Brady to see Myra Hindley.
Dr Grounds suggests that Brady would avoid making trouble if he went back to jail.
"He is a very astute observer, a strategist; this is somebody with the ability to weigh up what will happen if he misbehaves in prison. He might not care about the consequences - but they would offend his sense of superiority," Dr Grounds said.
Ms Eleanor Gray QC for Ashworth Hospital questions Dr Adrian Grounds on whether a return to jail would be suitable to Ian Brady - because his life in hospital is so much easier than a life behind prison bars.
She also suggests that Brady is deluded if he believes he will be treated better in prison.
She puts to him that Brady enjoys "reasonable" relationships with many members of staff at Ashworth, and that a prison regime would be far tougher and unsuited to his nocturnal habits. At Ashworth he is able to leave his room at night, and sleep during the day.
She also says that Brady is currently treated with tolerance - because everyone accepts he is unwell.
"[In prison] he's going to be treated as making rational, competent choices, and be disciplined accordingly," she said.
In jail, Brady's "tendency to pick battles...coupled with his paranoia" will only create conflict, she said.