Charles Cullen is a former nurse who worked in various hospitals in New Jersey and Pennsylvania. He is known for being one of the most prolific serial killers in American history, with estimates suggesting he may have killed as many as 400 patients over a 16-year career. Cullen was arrested in 2003 and later confessed to his crimes, which involved administering lethal doses of medication to his victims. In 2006, Cullen was sentenced to multiple life terms in prison without the possibility of parole. His case raised significant concerns about hospital safety and the monitoring of medical professionals, leading to discussions about the need for better oversight in the healthcare system. Cullen's actions have had a lasting impact on how hospitals manage patient care and staff conduct.