Charles Edmund Cullen (born February 22, 1960) is an American serial killer. While working as a nurse, Cullen murdered dozens—possibly hundreds—of patients during a 16-year career spanning several New Jersey and Pennsylvania medical centers until finally being arrested in 2003. He confessed to committing as many as 40 murders at least 29 of which have been confirmed, though interviews with police, psychiatrists and journalists suggest he committed many more. Researchers have suggested that Cullen may have murdered as many as 400 people. However, most murders cannot be confirmed due to lack of records.