On a beautiful morning in September 1852, a handsome couple stepped onto a hired boat in Howth Harbour bound for a picnic on Ireland’s Eye, a small uninhabited island less than a mile to the north of the harbour. William Burke was an artist, Maria Kirwan a keen and adventurous swimmer. By sunset, when the boatman returned to fetch them, she would be dead, found on a rock covered in blood.

Despite witnesses at the harbour hearing screams, the inquest ruled that it was a drowning, and Maria Kirwan was laid to rest. Then a startling secret emerged about the private life of her husband. After an exhumation, he was arrested for her murder. The case caused a sensation, the public fascinated by its extraordinary elements. Added to this and almost eclipsing the murder was the scandal: a sexual triangle that aroused the full force of Victorian moral outrage.

The trial was destined to become steeped in controversy and a veil of mystery has hung over the death of Maria Kirwan for the last 160 years. But now, at last, a forgotten medical paper has thrown light on what really happened on that fateful day.