Police superintendent Percy Trethowan found London’s Soho as colourful and full of life as ever – except for the four corpses in a seedy photography studio.Shot doing a layout for Bodies, a soft-porn “health and fitness” magazine, the photographer, his assistant, and two models had left a camera loaded with film but no clues.Then one victim’s obsession with pumping iron sent Trethowan into the erotic world of body-building, where an out-of-shape policeman would learn that bulging biceps were beautiful and the temptations to star in the buff in the bluest of movies could really be murder.