Police investigating the murder of Renee MacRae and her young son are ready to act as work on dualling the last section of the A9 begins next week.
Officers will be monitoring ground investigation works, due to start on the road between Tomatin and Moy on Monday.
Mrs MacRae, 36, and her three-year-old son Andrew have not been seen since November 12, 1976 – when her fire-damaged BMW car was found in a lay-by near Tomatin with a bloodstain in the boot.
Since then speculation about the whereabouts of their bodies has focused on the A9 – which was being rebuilt at the time – and particularly Dalmagarry Quarry.
Police confirmed that they are constantly working to identify any “new available investigative opportunities” – including working with roads agencies dualling the road.
It is understood that police have not made any request to Transport Scotland at this stage about the ground investigations due to start in the area on Monday.
Work to actually construct the new road remains some years away.
But protocols are in place should anything of interest be discovered at any point.
Detective Superintendent Jim Smith said: “The investigation into the murder of Christine MacRae remains ongoing, 40 years on from her disappearance.
“The investigation is subject to regular and on-going review within the Homicide Governance Review Unit in order to identify any new available investigative opportunities.
“This includes linking in with the local authority around the planned upgrade works for the A9.
“Police Scotland has established protocols in place should any evidence be discovered during the works on the A9 upgrade and will investigate any information received about the murder of Christine MacRae.”
A Transport Scotland spokesman said: “We are aware of the case and would be happy to provide assistance for Police Scotland as required.”
The police are also working with staff from the cold case unit at the Crown Office and Procurator Fiscal Service “to ascertain if there are any new evidential developments, including advances in forensic techniques, which could assist in providing a basis for criminal proceedings”.
A radar survey in 2006 commissioned by local farmer Brian MacGregor identified an “anomaly” beneath the northbound carriageway near Moy.
