A bone found in an independent search for the remains of murder victim Muriel McKay is not human, police have said.
Excavators working for the family of Ms McKay had discovered the bone at a site where they were told her body was buried 57 years ago.
But police have now said the bone - which is about nine inches long and a couple of inches wide - was not of human origin.
The discovery was made about a metre down in the back yard of a betting shop in Hackney, east London.
The Metropolitan Police said in a statement: "Police are aware of reports surrounding the discovery of a single bone in the garden of a property in Bethnal Green Road, Hackney. The bone was uncovered on Friday, 20 March, during an independent search.
"Officers attended the scene assisted by forensic colleagues who have determined the bone does not belong to a human."
Ahead of the origin of the bone being confirmed, Ms McKay's grandson Mark Dyer said: "It would be a great outcome to end this ghastly mystery for our whole family and all of those who've been interested enough to follow our story.
"Four years of intense investigation have led us here and we're waiting to hear if the bone is human. It's been found in a place we were told to look last year."
Ms McKay, 55, was the wife of Alick McKay, the deputy to newspaper mogul Rupert Murdoch, when she was kidnapped by brothers Arthur and Nizamodeen Hosein from her home in Wimbledon just after Christmas in 1969.
They mistook Ms McKay for Murdoch's wife Anna, held her at their ramshackle farm in Hertfordshire and demanded a million pounds for her safe return.
The bungling brothers were arrested and convicted at the Old Bailey of Ms McKay's murder, one of the first murder trials with no evidence of the victim's body. They never revealed her fate.
Five years ago, the family tracked down Nizamodeen to his native Trinidad and I flew with them to witness the extraordinary meeting.
Diane and her son Mark Dyer greeted the now-wizened old killer with hugs and persuaded him to confess to a crime he had always denied.
Nizam, now 79, told them Ms McKay had collapsed and died from a seizure within a few days and he buried her on the farm, pointing to old photographs and maps and indicating a precise spot "three yards from the fence".
On his word, Scotland Yard reopened its investigation and dug twice at the farm. They found no trace of Ms McKay and concluded that Nizam was wrong or was not telling the truth.
Read more:
Met police to interview McKay killer
Killer tells police where he says he buried body
Last year, the family issued a £1m reward for information and were contacted by Hayley Frais in Israel who told them her late father Percy Chaplin ran a tailor's shop in Bethnal Green in the 60s and 70s.
He made suits for his neighbours, the notorious gangster brothers Ronnie and Reggie Kray, but also employed Arthur Hosein.
Hayley said that on his deathbed three years ago her father told her of his long-held suspicion that a criminal associate of Arthur's dug up Ms McKay's body at the farm and re-buried it behind his premises, which is now the betting shop.
(c) Sky News 2026: Bone found in search for remains of Muriel McKay is not human, say police
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