The Press Association (UK) reports that a rare volume "believed to be bound in the skin of a priest executed for treason appears to bear a 'spooky' image of his face on the cover, according to the auctioneers who are selling the book."
The book, A True And Perfect Relation Of The Whole Proceedings Against The Late Most Barbarous Traitors, Garnet A Jesuit And His Confederates (London: Robert Barker, 1606) is an 'official' account of the trial and execution of Father Henry Garnet, hanged for treason after the Gunpowder Plot (he claimed to have known of the plot but that he did nothing to support it).
Soon after Garnet's execution, a piece of bloodstained straw from the hanging site was found which supposedly bore the image of the priest (called a martyr by some Catholics). The straw is known to have existed through the time of the French Revolution.
The article does not indicate why the book is believed to be bound in Garnet's skin, but it does include a comment from Sid Wilkinson, who'll be selling the volume at auction in South Yorkshire on Sunday. "It's a little bit spooky because the front of the book looks like it has the face of a man on it, which is presumed to be the victim's face," Wilkinson says.
I've been unable to locate a description of the book on the auction house website, so I've shot off an email to Mr. Wilkinson asking for provenance information about the book and for any images of the 'spooky face.' Stay tuned.
[Update: Images and more discussion, here]