Philip Stinson, criminologist at Bowling Green State University, who compiled the statistics, says the importance of video was highlighted last week with the release of footage showing a Chicago officer fatally shooting a teenager 16 times.
Officer Jason Van Dyke was charged with first-degree murder last week in that case. In the past, the annual average was fewer than five officers charged. In the final weeks of 2015, that number has climbed to 15, with nine of the cases involving video.
ABC’s Scott Goldberg has details from New York.