This research is part of a larger study of police crime—that is, crime committed by nonfederal sworn law enforcement officers with general powers of arrest—across the United States. In 2014, after several fatal on-duty police shootings garnered national media attention, our principal investigator, Philip Stinson, conducted a joint research project with The Washington Post to count the number of police officers charged with murder or manslaughter resulting from an on-duty shooting where the officer shot and killed someone. The results of the joint research project were published in The Washington Post on April 12, 2015, and The Washington Post was awarded the 2016 Pulitzer Prize for National Reporting, in part, for this project. The Police Integrity Research Group at Bowling Green State University continues to keep the information current, and new cases are added periodically to the count of officers charged with murder or manslaughter resulting from an on-duty shooting.