A fiendishly difficult murder-mystery puzzle in the form of 100 picture postcards: the official follow-up to Cain’s Jawbone by its first modern solver and creator of BBC Radio 4’s 'Cabin Pressure', John Finnemore.

Cain’s Jawbone, by Edward Powys Mathers writing as Torquemada and published in 1934, is a murder mystery in which the pages had been printed out of order. Only two people solved the puzzle back in the 1930s and the first person to solve it since was John Finnemore. He did so over a period of six months during the 2020 COVID lockdown.

Inspired by his experience, John decided to create his own version, The Researcher's First Murder.

A body is found stabbed to death in a locked room. The police find no weapon, no motive and no suspects. However, the murderer has in their possession a box of one hundred cryptic picture postcards which – if properly understood – would explain not just this murder, but nine others. The reader is now in possession of those cards.

Solvers must rearrange the pages of text to unravel the story and identify the murderer, victim and location for each of the ten murders. They must also consider the separate puzzles presented by the curious images on the other sides.

As with the original Cain’s Jawbone, there is a cash prize of £1,000 from publisher Unbound for the first person to solve all the elements of the The Researcher's First Murder. The competition will run for six months from the date of publication (22 August 2024).