The shock of the rare burst of violence was multiplied by its odd circumstances: In a picturesque and normally placid little German city, three bodies lay in a hotel room, each one killed with a crossbow.

More than 480km away, another gruesome discovery made the case still more confounding. Searching the home of one of the three people who had died in the hotel, police found two more bodies.

German authorities are now trying to piece together a mystery that has attracted international attention, and identify the motive or motives behind five deaths in a country whose homicide rate is