The Fire Engine That Disappeared by Maj Sjowall and Per Wahloo (1970)

 Ten yards away stood a long dismal figure, a pipe in his mouth and hands thrust deep down in his coat pockets.  This was Frederik Melander of the Homicide Squad in Stockholm and a veteran of hundreds of difficult investigations.  He was generally known for his logical mind, his excellent memory and immovable calm.  Within a smaller circle, he was most famous for his remarkable capacity for always being in the toilet when anyone wanted to get hold of him.  His sense of humor was not non-existent, but very modest; he was parsimonious and dull and never had brilliant ideas or sudden inspiration.  Briefly, he was a first-class policeman.

Maj Sjowall and Per Wahloo, The Fire Engine That Disappeared, (Random House, 1970, translated from the Swedish by Joan Tate)

This is the fifth novel about Stockholm policeman Martin Beck by Sjowall and Per Wahloo, though in this novel Martin Beck has rather a small part, as all the members of his squad work for months to solve the problem of an apartment house that blows up when a man is killed while attempting suicide, with a bomb and gas destroying a building and killing some its tenants.  The squad works together, from bullying veteran Gunvald Larsson to rookie Benny Skacke, who hopes to be commissioner some day, but make little progress until their major suspect turns up dead in Malmo, having died before the apartment fire, and where a local policeman helps track down who was actually responsible.

This book in the series emphasizes the personal lives of the Homicide Squad, of whom some are happily married, some unhappily married and some not married at all, and how their love lives affect their work.  The Fire Engine That Disappeared is full of the irony that Wahloo and Sjowall use effectively to portray not only the working of the Homicide Squad but also the lives of Swedish citizens who are affected in greater and lesser ways by both the criminals and police.