Robert Ressler

Robert Kenneth Ressler (February 21, 1937 – May 5, 2013) was an 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.