« The Blind Barber » John Dickson Carr

A thief is loose aboard HMS Queen Victoria, and four amateur detectives are hell–bent on tracking him down. Unprepared for the evidence that their sleuthing activities will uncover — a reel of compromising film, a blood–soaked stateroom bunk, a lethally sharp razor and an emerald elephant — they find themselves sinking deeper into misadventure and pandemonium. But when the boat arrives in Southampton harbour, another passenger, mystery writer Henry Morgan, calls in the famous Dr Gideon Fell — who identifies sixteen clues that lead him to the murderer.