A quarry is to be drained as part of a police investigation into the disappearance of Inverness mum Renee Macrae and her toddler son Andrew Macrae more than 40 years ago.
The pair disappeared on November 12, 1976.
Police searched the flooded Leanach quarry at Culloden Moor on the eastern side of Inverness last year.
Detectives have been carrying out a review of all of the evidence gathered over more than four decades, which has led directly to the search of Leanach Quarry, which is expected to start in the coming days.
Senior investigating officer Detective Inspector Brian Geddes said: “This is a significant development in the ongoing investigation into the murders of Renee and Andrew MacRae.
“Work is now underway to carry out a forensic search of Leanach Quarry where we believe key pieces of evidence may have been concealed.
“A key part of this operation is to recover the remains of Renee and Andrew if they are within the quarry, and gather evidence vital to this on-going investigation.”
Last November Police Scotland revealed it had a team of detectives working to “identify new lines of inquiry and develop any existing lines of inquiry” in the case.
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And now the force is set to embark on a more detailed search of the quarry, which was searched in the months following the disappearance of the mother and son.
Mrs MacRae, then aged 36, left her home in the Cradlehall area of Inverness with both her sons, before dropping Gordon with her estranged husband, Gordon MacRae.
She drove south on to the A9, reportedly to meet her lover, Bill MacDowell, an accountant in her husband’s building company, with the couple said to be planning to start a new life.
Her burnt-out BMW was found with a bloodstain in the boot in a lay-by, a mile south of Tomatin.
A murder inquiry was launched, but no bodies have ever been found and no one has ever been convicted of their killing.
Detective Inspector Geddes said last year the major investigations team was “poring through every single” item of information held about their disappearance to find new angles and develop existing lines of inquiry.
“All the indications are that Renee and Andrew came to harm 42 years ago and as such this is being progressed as a murder investigation,” he said.
“We are applying the most modern techniques in a bid to progress the investigation and this will include utilising advances in forensic science. Our goals are to bring a person, or persons, to justice and to locate the remains of Renee and Andrew to bring some form of closure to Renee’s sister Morag and the rest of the family.”