Ever since F.X. Flynn made his first appearance in Confess, Fletch, matching wits with the inimitable Irwin Fletcher, he has befuddled, infuriated, and amazed his colleagues on the Boston Police force while in pursuit of blackmailers, murderers, embezzlers, politicians, and, occasionally, his fellow policemen. It might have been an accident that brought down the Boeing 707 over Boston Harbor, virtually in Flynn's own backyard. But it seems unlikely,...