In an effort to determine what circumstances were the most dangerous for law enforcement officers in the field, the National Law Enforcement Officers Memorial Fund (NLEOMF) conducted a study titled Deadly Calls and Fatal Encounters. In this study of law enforcement officers’ line-of-duty deaths, funded by the Community Oriented Policing Services (COPS) Office, the National Law Enforcement Officers Memorial Fund (NLEOMF) analyzed four years of cases in which officers responding to a complaint or call for service were killed in the line of duty. Nick Breul and Michael Keith of the NLEOMF’s Officer Safety, Wellness, and Research Department leveraged the organization’s extensive database and case files to cull through 684 fatality cases between 2010 and 2014 to determine which of those cases involved an officer being dispatched to a call for service and the circumstances of each particular call that resulted in a line-of-duty death.