A quarry will be completely emptied of water to allow police to continue a murder investigation into the disappearance of a mother and her three-year-old son more than 40 years ago.

Renee MacRae and her son Andrew were last seen driving out of Inverness on November 12, 1976.

The 36-year-old mother-of-two’s BMW was found burned out in a lay-by on the A9 near Dalmagarry, 12 miles south of the city, but the pair have not been seen since.

A forensic search of Leanach Quarry is expected to start in the coming days, the latest attempt in an investigation spanning more than four decades and now led by Police Scotland’s major investigation team.

Senior investigating officer Detective Inspector Brian Geddes said the quarry had previously been deemed too dangerous to search using divers, hence the decision to pump water completely from the site.

He hailed the move as a “significant development” in the case.

Mr Geddes said: “Work is now under way 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. I would also like to thank local landowners for their co-operation in this inquiry.

“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.”

In 2004, a full cold case review resulted in a month-long excavation of Dalmagarry Quarry.

Renee MacRae
Renee MacRae, 36, who disappeared with her three-year-old son Andrew more than 40 years ago (Police Scotland/PA)

Several days were spent at Leanach Quarry in October last year when officers also released an image of young Andrew around the time of what would be his 45th birthday.

A picture of his pram was also released, although it was never recovered.

DI Geddes 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.

“We intend to do everything we can to ensure that any key pieces of evidence which we believe are in there are recovered.

“I would also appeal to anyone with information to please come forward and speak to us.”

Anyone who believes they can assist police is asked to contact 101, e-mail a dedicated inbox at SCDHOLMESInverness@scotland.pnn.police.uk, or contact Crimestoppers anonymously on 0800 555 111.