Jewellery worth £10,000 found in serial killer Harold Shipman's garage may have been stolen from some of his victims, police have said.
Shipman killed an estimated 250 people between 1971 and 1998
Police have now written to the families of the former Hyde GP's victims, asking them to identify the jewellery.
Items that the Shipman family could prove belonged to them have already been returned, said police.
Solicitors acting on behalf of his widow, Primrose, have asked for all items to be given back to her.
The solicitors - Pannone and Partners - have declined to comment on the issue.
Greater Manchester Police said the collection of rings, brooches, earrings, bracelets and necklaces were of "varying estimated values".
"No evidence was found to support the theory at the time, that it was stolen property, but it has always been our unsubstantiated belief that some of that jewellery may have belonged to Shipman's victims," a police statement said.
Items that cannot be identified will be returned to Primrose
"We have written to the families of Shipman's victims, via Victim Support and Alexander Harris solicitors, in a final attempt to establish if anybody can positively identify any of the items in our possession as having belonged to their loved one.
"We have asked that people provide either a receipt for the item, photographic evidence of its existence or a detailed description of the item in question, before Friday 15 April 2005.
"Jewellery that cannot be positively identified will be returned to Dr Shipman's next of kin as required under the Police Property Act."
Police said they had contacted "at least 180" families.
Bill Catler, a friend of Lizzie Adams - one of Shipman's victims - says he thinks he may have foiled the doctor's attempts to take her belongings.
He found Mr Shipman at her house shortly after she was killed.
"It wouldn't surprise me at all because he had time to look around the houses of the victims," he said.
"I arrived dead on time."
Ann Alexander, the solicitor representing Shipman's victims and their families, said: "Families will be relieved that at long last they are hearing from the police with a view to finding out if there is anything held in stores which belongs to them."
The official inquiry into the serial killer's crimes found he killed an estimated 250 people during his time as a doctor in Hyde, Greater Manchester and Pontefract and Todmorden, West Yorkshire, between 1971 and 1998.