Black Heart: A totally gripping serial killer thriller

There's a letter on the floor covered with blood next to a heart-shaped box of chocolates. The note says: 'My beautiful darling, I'm sorry, please forgive me.' When the body of a man is found with his wrists slashed in a London hotel room, it appears at first to be a tragic suicide. But Detective Dan Riley suspects there is more to this case than meets the eye and the pathology report confirms his worst fears - the victim was poisoned and suddenly Dan is dealing with a murder inquiry. Still...