Robert Ressler, American FBI agent and author (born 1937)

Robert Kenneth Ressler was an American FBI agent and author. He played a significant role in the psychological profiling of violent offenders in the 1970s and is often credited with coining the term "serial killer", though the term is a direct translation of the German term Serienmörder coined in 1930 by Berlin investigator Ernst Gennat. After retiring from the FBI, he authored a number of books on serial murders, and often gave lectures on criminology.

The Federal Bureau of Investigation (FBI) is the domestic intelligence and security service of the United States and its principal federal law enforcement agency. An agency of the United States Department of Justice, the FBI is a member of the U.S. Intelligence Community and reports to both the attorney general and the director of national intelligence. A leading American counterterrorism, counterintelligence, and criminal investigative organization, the FBI has jurisdiction over violations of more than 200 categories of federal crimes. The FBI maintains a list of its top 10 most wanted fugitives.