The Fire Engine That Disappeared
Per Wahlöö
 A house fire, which kills three people, was about to be written off as the result of a tenant's gas suicide when a forensics officer discovers a firebomb in the rubble that would have certainly killed the tenant had he not killed himself. Beck and his team launch a manhunt for the tenant's partner-in-crime, but are perplexed when the partner-in-crime is found dead at the bottom of the sea.