Harry Donner, one of three men wanted by our bureau for bank robbery was killed by a bomb as he took a suitcase out of a locker in a downtown station. Fortunately, no-one else was near the locker at the time. There were no immediate clues as to who had setup this threat. When Donner's body was removed to the morgue, the only items found in his pocket were a five dollar bill, and a book of matches. Your FBI began the search for his killers with that book of matches...