The killings – which became known as the Jigsaw Murders – took place in September 1935.
Newspaper reporters flocked to Dumfries and Galloway after dismembered and disfigured human remains were discovered beneath a bridge over a stream.
The remains were sent to Edinburgh University, where forensic scientists and colleagues from Glasgow University pieced together the body parts.
As they carried out their gruesome task, another investigation was under way 100 miles south in Lancaster, north west England.
Dr Buck Ruxton had given various explanations for the disappearance of his wife Isabella and their nursemaid Mary Rogerson.
The popular GP had been jealous of his wife’s friendship with other men.
She had accused him of domestic abuse before she vanished but local police had taken no action.
Mary and Isabella were reported missing by Mary’s family, not by Ruxton.
