John Patrick St. John (February 18, 1918 – May 3, 1995), better known as "Jigsaw John", was an American police officer and Los Angeles Police Department homicide detective, renowned for his investigations of many of Los Angeles's highest-profile murder cases. Upon his retirement in 1993, St. John held the highest seniority on the LAPD with 51 years of service, a distinction that earned him the privilege of carrying LAPD Detective badge No. 1.
