The fire engine that disappeared

An incendiary device blows the roof off a Stockholm apartment, interrupting the small, peaceful orgy underway inside, and nearly killing the building's eleven occupants. And if one of Martin Beck's colleagues hadn't been on the scene, the explosion would have led to a major catastrophe because a regulation firetruck has vanished. And what did the explosion have to do with the peculiar death earlier that day of a forty-six-year-old bachelor whose cryptic suicide note consisted of only two words: 'Martin Beck'?