Purity Squad: This entry in the Crime Does Not Pay series focuses on the U.S. Food and Drug Administration's effort to ensure that drugs are fully tested before they are sold to consumers. Two unscrupulous investors market the drug 'Diabulin' as a substitute for insulin after preliminary tests show good results. After a short time, however, users start dying from the drug. The FDA and the state attorney general's office then go after the drug marketers.