Robert K. Ressler

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