Last month in the Cleveland town of Hartlepool, a cash security van was attacked as it stopped at a housing estate sub-post office. Five masked men, armed with pickaxes, a shotgun and ammonia spray, got away with many thousand pounds in cash and stamps. Witnesses who tried to call the police found their phones were dead. The gang had cut lines to the whole estate. Five cars were used in the robbery, all of them stolen in the North. One, a rare type of BMW, was taken in September. Where was it kept for those four months? A viewer who remembers seeing the car could lead police to the men they must catch.