Moors murderer Ian Brady's mental health advocate will not be charged over allegations she failed to tell the police about a letter which may have revealed where one of his victims was buried, the Crown Prosecution Service said.
Jackie Powell was arrested on suspicion of preventing the lawful burial of Keith Bennett after she told a television documentary that Brady had given her a sealed envelope to pass to Winnie Johnson, Keith's mother, in the event of his death.
The letter was never found and Mrs Johnson died last August still not knowing where her son was buried.
John Dilworth, head of the CPS North West Complex Case Unit, said: "After careful consideration, we have decided that Ms Powell should not be charged, as it cannot be established that she knew the contents of the letter referred to, that the letter in question existed or what information it might have contained.
"The only evidence of the letter's existence was in comments given by Ms Powell to an interviewer and she stated only that she believed it may contain information about Keith Bennett."
Mr Dilworth said: "The only offence that might have been committed by Ms Powell was preventing a lawful and decent burial. It is possible to prosecute a person for preventing a lawful burial through a failure to act, but there must be sufficient evidence to prove that the suspect either prevented the burial or intended to do so when they chose not to act."
He added: "Even if it could be proved that this letter existed, there is no evidence to suggest that Ms Powell ever knew the nature of its contents and there is insufficient evidence to prove that she genuinely believed it contained the information in question. As such, it could not be established in court that Ms Powell either prevented Keith Bennett's burial or intended to do so. We understand that this is still a very sensitive matter for the relatives of Keith Bennett. We have written to Keith Bennett's brother to explain our decision and have offered a meeting to discuss this matter."
Martin Bottomley, head of investigative review in Greater Manchester Police's major and cold case crime unit, said: "As soon as we were made aware of the existence of this alleged letter, we made exhaustive attempts to obtain it to establish whether or not its contents would assist us in finding Keith's body.
"That resulted in the warrants we carried out in the South Wales area and at Ashworth Hospital in August 2012. However, despite seizing numerous documents and a search of Brady's cell, no such letter has been recovered. That in itself does not prove or disprove the letter's existence. It might have been destroyed, it might be hidden elsewhere, it may be in someone else's possession, or it may simply never have existed in the first place and this has been yet more mind games by Brady."
Mr Bottomley added: "I do want to make this point however: this whole episode about the letter came at a time when Winnie was sadly in her final days. Winnie and the rest of her family have suffered unimaginable torment. Keith still has surviving relatives who deserve to know the truth and Greater Manchester Police will continue to act on any credible evidence to bring this torment to an end."