The brother of Moors Murder's victim Keith Bennett has asked a lawyer to "show compassion and understanding" and hand over the two sealed briefcases from Ian Brady.
Alan Bennett believes that they may contain clues as to the exact location Brady and Myra Hindley Keith had buried after kidnapping and killing him in 1964.
But Brady's lawyer, Robin Makin, has refused to forward the cases to GMP's Cold Case Unit Officers.
Shortly before his death in May 2017, Brady requested that the two associated suitcases should be kept safe.
It has now turned out that the officials went to court to file a search warrant to open the cases and look for clues.
However, a district judge denied the petition and said there was no prospect of investigations leading to prosecution since both killers were dead.
Before the court hearing, Mr. Makin had met GMP officials and brought the sealed briefcases. He refused, however, that the police examined Brady's personal papers.
Kay's brother Alan, 62, said, "There is a desperate need to look for something that can help restore Keith's body, and there could be something in those cases, we can not be sure we know need – one way or the other.
"In my correspondence with Brady many years ago, he said he had left instructions for me alone, he did not give any further details, but it was at a time when I was looking in the moor and asking him directions, areas of the moor, Sights etc.
"Mr Makin's refusal to help is a cause for concern, considering that my brother's body is still lying in the moor, while all other victims have been returned to their relatives for the proper burial.
"Of course, anything that could help bring Keith home must be made available to the police on behalf of his family." There does not seem to be any sympathy or concern for Keith or his family regarding Mr. Makin know his unwillingness to do anything to help us. "
"Now I need a little compassion and understanding shown by Mr. Makin, and when Brady said that he left orders for me, maybe it was one of his stupid games or something in the briefcases."
Alan spent most of the decade searching through Saddleworth Moor near the Shiny Brook River, with a team of volunteers digging peat after Keith's remains. Winnies Johnson, his and Keith's mother, who died in 2012, visited the Moore in a futile quest.
"I will not give up, I've had surgery recently, but if I'm fit, I'll go back there," he said.
"I think GMP should return tomorrow and continue the search that would be my choice, but I fully understand that they need more detailed information, and I know that Cold Case Unit officers also want to find Keith."
He has received help and guidance from forensic archaeologists in the past, but believes the contents of the briefcases could be a breakthrough.
Alan said, "After meeting with the Cold Case officials after he promised the police access to the papers, he just sat at a desk across the street while checking the newspapers and convincing himself that nothing was wrong was of interest to them.
"The police were not allowed to touch or read the papers, Mr. Makin was never in the moor or on the interesting side looking for Keith, and I doubt he would have recognized any name of an area that might have been A reference to Areas the bog would have known the police right away.
After Mr. Makin carefully scrutinized the papers and left the police on the opposite side of the desk angrily, the police were informed by Mr. Makin that he did not know the combinations for the two cases, but would make a locksmith to open it and when he had arranged an appointment for the locksmith, he invited the police again to be present.
"All this took place over a year ago and since that time he has ignored all further requests to access the contents of the case, which were made by the police and a lawyer working on my behalf.
"Mr. Makin also ignored a personal request from me in a letter to him and ignored a follow-up e-mail.
"I can not understand why the cases were not opened in the presence of the police and I can not understand the refusal to even accept the cold case team's requests to gain access to the case content.
Martin Bottomley, head of GMP's Cold Case Unit, said, "We will continue to do everything we can to trace all the investigative lines to find Keith's body and support his family and their efforts to discover the truth. We will never complete this case until we have the answers that really deserve it. "
Mr Makin from E Rex Makin & Co Solicitors in Liverpool declined to comment.
Keith was one of five children murdered between 1963 and 1965 by Brady and Hindlley.
He was 12 years old when he left for his grandmother's home in Longsight on June 16, 1964.
Keith's mother, Winnie Johnson, waved off as he crossed Eston Street. She would never see him again.
A short time later, just before Stockport Road, Hindley rolled down the window of her new Mini and asked Keith if he would mind helping her with some crates. Brady was sitting in the back of the car.
In 1986, after Hindley and Brady first confessed to killing Keith and Pauline Reade, GMP conducted a new search of the moors. The body of Pauline, who was 16 years old when she was killed in 1963, was found on July 1, 1987. After Pauline's remains had been found, the search for Keith was stopped.
Alan told Duncan Staff, author of The Lost Boy, an in-depth story of the search for Keith, that in the days following his brother's disappearance, he would climb the stairs to the bedroom he shared with him and stare at his empty bed ,
He said to Staff, "I lied there and talked to him, where are you Keith? Come back, he was like a presence that was still with me, but physically he was gone, and that has never changed was all those years with me. "