The Devil's Star

Given no choice in investigating two murders, Detective Harry Hole reluctantly teams up with Tom Waaler who Harry suspects of running an arms smuggling gang and of having murdered his partner. A common thread of riddles connects the cases - A riddle of fives: five-pointed stars, five fingers on the hand, and every fifth day a new victim to be counted. Harry is determined to prove that his hunch about Waaler is right, and he begins to wonder whether his enemy is somehow bound up with the killings.