The bodies of a missing Highland mother and her three-year-old son were not buried in a quarry south of Inverness, according to detectives.
The excavation of the quarry has proved fruitless
Renee and Andrew MacRae disappeared in 1976 after the mother's burned-out car was discovered in a lay-by on the A9.
Last month Northern Constabulary began a forensic excavation of nearby Dalmagarry quarry but now say no trace of the pair has been found.
However, officers insisted they may be able to make a case they were murdered.
The mystery of what happened 28 years ago has stuck firmly in the minds of people in and around Inverness and a review of the case prompted police to revisit the quarry.
At the time of the original investigation one officer reported smelling decomposing flesh in the area, which was never properly searched.
In August, police drafted in internationally experienced forensic archaeologists and anthropologists to sift 35,000 tonnes of soil from the disused quarry, but no sign of the pair was found.
Detective Superintendent Gordon Urquhart, who is leading the renewed investigation, said: "I think we've done a meticulous job and what we can confirm is that there are no bodies, there is no evidential material within the quarry area."
Former officer John Cathcart, who reported the odour of flesh, said he had hoped for progress.
Mr Cathcart said: "I was quite happy that something to explain the smell would have been found and the fact that nothing has been found frankly leaves me very disappointed."
Renee's sister Morag Govans, who lives in Inverness, said: "My hopes were raised a lot but they've been dashed several times over the last 28 years, so I always knew that they might not be found."
Renee and Andrew MacRae were last seen in 1976
Detectives revisiting the case are following other historical evidence and Det Supt Urquhart said it was still hoped enough of a case could be made to take a killer to court.
Renee MacRae had been having an affair with Bill MacDowell, who was her husband Gordon's accountant.
Mr MacDowell, who now lives in London, is the father of Andrew, who vanished along with his mother. He recently denied any involvement in their disappearance.
She had been said to be going to meet him on the night she vanished but Mr MacDowell said he decided against it.