Over a number of years, data collected by the FBI’s Law Enforcement Officers Killed and Assaulted {LEOKA} Program began to demonstrate an alarming trend in the number of officers who were killed in ambushes and unprovoked attacks. While the overall number of officers who were feloniously killed was declining, the percentage of officers feloniously killed during surprise attacks was increasing. The LEOKA Program launched a thorough examination of ambushes and unprovoked attacks in an effort to gain insight into the phenomenon and to provide information to enhance training programs for law enforcement officers. The research focused on the mindset and perceptions of officers involved and offenders who carried out those acts. In particular, why the incidents may have occurred and how those involved reacted to the situation.