From the Press Release: "In addition to the narratives, the online-only report includes comprehensive data tables that provide a closer look at the incidents: officer profiles, circumstances, weapons, locations, and identified suspects. The felonious deaths of the 51 officers--all males--occurred in 24 states and Puerto Rico. The figure represents a significant increase over the number that occurred in 2013, when 27 officers were killed, but is lower than the numbers from 2009 (56 officers) and 2005 (55 officers). […] The LEOKA [Law Enforcement Officers Killed & Assaulted] publication contains data on duly-sworn city, university/college, county, state, tribal, and federal law enforcement officers. The information in the report comes from various sources: the law enforcement agencies participating in the UCR Program, FBI field offices, and several non-profit organizations, such as the Concerns of Police Survivors and the National Law Enforcement Officers Memorial Fund. In addition to collecting details about the critical aspects of fatal confrontations and assaults, the FBI's LEOKA Program conducts extensive research on the data that eventually gets incorporated into officer safety awareness training the FBI provides for partner agencies."
Federal Bureau of Investigation: https://www.fbi.gov/