A flooded quarry is to be drained as part of a police investigation into the disappearance of a woman and her young son more than 40 years ago.
Renee MacRae, 36, from Inverness, and her three-year-old son Andrew disappeared on 12 November 1976.
Police searched the flooded Leanach quarry at Culloden Moor on the eastern side of Inverness last year.
But the abandoned quarry will now be drained and its sediment removed for forensic testing.
Last year 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.
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.
Search to begin
Det Insp Brian Geddes, senior investigating officer in the case, said: "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.
"We are working with a number of different partners on what will be a challenging and complex operation expected to last several weeks.
"The quarry has previously been deemed too dangerous to search using divers, which is why the decision has been made to pump the water completely from the site.
"We will thereafter remove the sediment from the quarry, which will allow specialist search officers and forensic experts to carry out a meticulous search of the material."
He added: "It is a major undertaking for everyone involved but the determination remains within Police Scotland to solve this case and bring closure to Renee and Andrew's family and friends after all these years."
On the evening of her disappearance, Mrs MacRae, who was estranged from her husband Gordon, had set off for Perth with the youngest of her two sons, Andrew, to meet her lover Bill McDowell, Mr Macrae's married accountant.
He told police they never met.
Mrs MacRae's burned-out BMW car was discovered on the night she disappeared in a lay-by on the A9 south of Inverness.
There has been speculation that Mrs MacRae and her son were murdered and their bodies buried at either a quarry or at construction works for the A9.
In 2016 a report naming a suspect who may have killed the pair was sent by the police to prosecutors but they decided there was insufficient evidence to take action.
Since then the investigation into the disappearance has continued, with fresh appeals and pictures released to the public.