After he shot off a man's face and beheaded a woman in Broward County, Florida, Carlos Stier started working as an informant for the Drug Enforcement Administration. His work led him to cross paths with another informant, Julio Diaz, a physician and Bay of Pigs veteran who had worked for both the FBI and CIA in matters deemed secret because they affect the security of the United States of America. The two undercover operations collided, and after...