A 77-year-old man has been arrested in connection with the deaths of a mother and her young son more than 40 years ago.
Renee MacRae, 36, from Inverness, and Andrew, three, vanished on 12 November 1976.
Police said the man was expected to appear at Inverness Sheriff Court on Wednesday.
Mrs MacRae’s car was found on fire close to the A9 by a passing bus driver about 12 miles south of Inverness.
The bodies of the mother and son have not been found, police said.
The man was arrested in the north of England on Wednesday morning by detectives from Police Scotland’s Major Investigation Team.
Police Scotland said a “detailed forensic search” of Leanach Quarry, near Inverness, started earlier this year in connection with the investigation was continuing.
Det Insp Brian Geddes said: “This is a significant development in an investigation which started when Renee and Andrew disappeared in November 1976.
“Their disappearance has had an unimaginable impact on the lives of Renee and Andrew’s family and friends for several decades.
“This has also been felt keenly in Inverness, but also across Scotland and beyond.”
The detective added: “Police officers and staff from across the country, as well as a number of partner agencies and contractors, have put an enormous amount of work into this investigation from 1976 to the present day, allowing us to reach this point.
“The remains of Renee and Andrew have not been recovered, however, the searching of a large quantity of material removed from Leanach Quarry continues.”