Police have ended a search for Moors murders victim Keith Bennett on Saddleworth Moor after finding no human remains.
An author claimed to have found evidence of the possible burial site of the 12-year-old boy who went missing in 1964 and whose body has never been found.
Keith was one of five victims of Ian Brady and Myra Hindley, with three of them later found buried on the moor.
Greater Manchester Police (GMP) began searching the area on 29 September but on Friday said there was "no evidence of the presence of human remains".
Detective Chief Inspector Cheryl Hughes said: "The investigation into Keith's disappearance and murder has remained open since 1964 and it will not be closed until we have found the answers his family have deserved for so many years.
"The excavation and examination at the site is complete and, to reiterate, we have found no evidence that this is the burial location of Keith Bennett."
Author Russell Edwards told the Daily Mail he believed he had located Keith's makeshift grave following "extensive soil analysis" which indicated the presence of human remains.
Mr Edwards is said to have commenced his own dig - close to where the other Moors murders victims were found - and uncovered a skull with teeth, which independent experts are reported to have concluded is human.
DCI Hughes said officers "met with the member of the public who later provided us with samples and copies of the photographs he had taken".
"He also took officers to the location from which he had obtained these and provided grid references," she added.
The senior investigating officer said experts had completed an examination of the site, adding: "The items given to us by the member of the public have been examined by a forensic scientist and though this hasn't yet indicated the presence of human remains - more analysis is required."
GMP previously said it was provided with a photo showing what experts working with Mr Edwards had interpreted as a human jaw bone.
But DCI Hughes said on Friday: "At this stage, the indications are that it would be considerably smaller than a juvenile jaw and it cannot be ruled out that it is plant-based."
Keith Bennett's brother Alan had previously expressed doubt that the author's findings would turn out to be the remains of his sibling.
Writing on Facebook after the search of the site began, he said he "cannot escape the feeling that we have been here before".
Brady and his accomplice Hindley sexually assaulted, tortured and murdered children over two years in the 1960s.
While the bodies of four of their victims were discovered, Keith's remains have never been found.
Keith was last seen by his mother in the early evening of 16 June 1964 after leaving his home in Longsight, Manchester, on his way to his grandmother's house nearby.
Brady told Hindley he sexually assaulted and strangled the boy.
Despite a plea to Brady from Keith's mother, Winnie Johnson, to reveal the details of where her son's body was, holding back the information was believed to be the killer maintaining a last element of control.
Mrs Johnson died in 2012 without fulfilling her wish to give him a proper Christian burial.
Brady confessed to Keith's murder but claimed he could not remember where he was buried.
Brady and Hindley's other victims were 16-year-old Pauline Reade who disappeared on her way to a disco in July 1963; 12-year-old John Kilbride who was snatched in November the same year; Lesley Ann Downey, aged 10, who was lured away from a funfair on Boxing Day 1964; and 17-year-old Edward Evans who was axed to death in October 1965.
The killers were caught after the Evans murder and Lesley and John's bodies were recovered from the moors.
Hindley died in jail in 2002 at the age of 60, while Brady died in a high-security hospital in 2017 aged 79.