David Allen Grossman (born August 23, 1956) is an American author and trainer who conducts seminars on the psychology of lethal force.
Following his retirement from the Army, Grossman founded the Killology Research Group to give seminars about the physiological and the psychological effects of having to use lethal force for law enforcement officers and soldiers.
"[4] Grossman's response to Engen, printed in the same journal, attempted to address the criticisms by arguing that SLA Marshall's findings that man is not by nature a killer, even after having doubt cast on their methodology, have borne out in further scientific studies and real world experience, and furthermore, "have been the cornerstone of military and police training for over a half century.
[6] University of Nebraska criminal justice professor Samuel Walker characterized Grossman's training as "okay for Green Berets but unacceptable for domestic policing.
"[7] Minneapolis Mayor Jacob Frey banned what he termed "fear-based training," a designation that included Grossman's seminars, in 2019.