Protests about the shooting of an unarmed teenager in Missouri by a police officer are still ongoing. Other controversial shootings by law enforcement officers have happened more recently. Statistics on the number of people who are shot and killed by law enforcement each year are available in the Federal Bureau of Investigation's annual publication Crime in the United States.
title of the table is "Justifiable Homicide," so the FBI, at least, is
convinced that every case is "justifiable." The folks in Missouri don't
seem to agree. (But, of course, Missouri is the "Show Me" state.)