Dr Caroline Muirhead helped lead police to the spot where Tony Parsons had been buried after a confession from her boyfriend.
Police are calling for information from the public about the accident, which happened about 11:30 on Friday.
The five-week stretch of dry weather will come to an end later with heavy rain, hail and thunder due over the weekend.
Temperatures rose above 25C in parts of the country but major rivers are under low water alerts.
Tony Parsons, 63, was killed by a drink driver who later hid his body in a shallow grave on a remote Scottish estate.
George Murphy admitted causing the deaths of Martin and Josephine Cousland on the A85 in 2023.
David White, from Sheffield, died when his lorry overturned on the A82 in Stirlingshire, police say.
The 61-year-old lorry driver was pronounced dead at the scene after the crash between Crianlarich and Tyndrum.
Four people were injured in the two-car crash on the A85 between Dalmally and Tyndrum on Sunday.
