Cash Collectors

The story

News about attacks on cash collectors in our time, alas, has become something everyday, but this event literally shocked the public: one employee of a well-known collection service was killed, another was seriously injured. The bloody crime was committed so clearly and smoothly that the investigators cannot help but suspect that the raiders have an informant among the collectors. What they don't suspect is that much more money was stolen than is listed on the documents: there was "black cash" in the car, which the authorities should not know about.