Three friends are exploring an abandoned mineshaft in Wales when they stumble upon a human skull. As the police arrive to search the area, they continue to make a number of gruesome discoveries. And they find something else: a diamond engagement ring.

Did these three young men just accidentally crack a 42-year-old cold case? Laura and Iain dig into the eerie 1919 disappearance of Mamie Stuart.

Murder They Wrote with Laura Whitmore and Iain Stirling is available twice a week on BBC Sounds. Subscribe now so you never miss an episode. Got a case or story for us? Email [email protected].