THE CASE OF THE PURPLE MARK

A trumped-up mystery involves the theft of valuable scientific data for a foreign power and the detecting of the high school kids who solve it. Gordon, a brain in chemistry, Pete, an athlete, and their friend Julie, are wandering by the school chemistry lab one evening talking about their good friend Prof. Nordland, when there is a big explosion. Nordland is killed and as the investigations get under way it is Gordon who helps figure things out and convinces the police of a plan to catch the culprit. A lure, containing the secrets of the work Nordland was doing for the government, is planted and coated with gentian violet, which reveals Dyer as the thief.