The Token — Gerald Verner

Four murders in just over a month, and not the ghost of a clue as to who has committed them - except that in each case a little silver bell was left on the body of the victim. Under pressure from all quarters, Detective-Inspector Shadgold seeks the help of his friend Trevor Lowe, the famous criminologist. But Lowe has nothing to go on, either - until he is approached by terrified film star Gloria Swayne, who reveals that the first victim of the silver bell killer had been her secret fiance...