 In the field, he served as a sniper on the local FBI SWAT team and later became a hostage negotiator.He transferred to the FBI's Behavioral Science Unit (BSU) in 1977 where he taught hostage negotiation and applied criminal psychology at the FBI Academy in Quantico, Virginia to new FBI special agents, field agents, and police officers from all over the United States.He created and managed the FBI's Criminal Profiling Program and was later promoted to unit chief of the Investigative Support Unit, a division of the FBI's National Center for the Analysis of Violent Crime (NCAVC).