3. Michael Swango
Though only legally accused of three murders, many say that Michael Swango killed at few as 30 people, but as many as 60 during his career as a doctor in several different states and medical facilities. It all started when he entered Southern Illinois University Medical School and was said to have a fascination with dying patients. After graduating, despite being expelled, he was accepted for an internship at Ohio State University. On the floors that he worked on, nurses often saw that these patients, who were once healthy, would die without warning. At one point, a nurse saw him injecting something into a patient who later became ill. After losing the internship he went back to Inllionis and worked as an E.M.T., where he would poison the paramedics. He was eventually arrested for possession of arsenic and other types of poison. After more deaths and conflict, Swango was caught, and admitted to killing three of his patients. Today, Swango is serving his life term in ADX Florence.