Overview: Dr. Michael Swango took an oath to “do no harm”… But he did just the opposite. Suspicious illnesses and deaths followed this once-trusted physician-turned-killer from hospital to hospital for nearly two decades and across two continents. His prey – unsuspecting coworkers and helpless patients. What would make a well-respected doctor become one of the most prolific serial killers in the U.S.? Interviews include survivors, Swango’s former colleagues, families of his victims, federal and local investigators, and a Zimbabwe journalist who helped uncover a series of murders in a rural African hospital.