Allegations of the use of excessive force by U.S. police departments continue to generate headlines more than two decades after the 1992 Los Angeles riots brought the issue to mass public attention and spurred some law enforcement reforms.

On Staten Island, N.Y., the July 2014 death of Eric Garner because of the apparent use of a “chokehold” by an officer sparked outrage. A month later in Ferguson, Mo., the fatal shooting of teenager Michael Brown by officer Darren Wilson ignited protests, and a grand jury’s decision not to indict Wilson triggered further unrest. In November, Tamir Rice was shot by police in Cleveland, Ohio. He was 12 years old and playing with a toy pistol. On April 4, 2015, Walter L. Scott was shot by a police officer after a routine traffic stop in North Charleston, S.C. The same month, Freddie Gray died while in police custody in Baltimore, setting off widespread unrest. The policeman in the South Carolina case, Michael T. Slager, was charged with murder based on a cellphone video. In Baltimore, the driver of the police van in which Gray died, Caesar Goodson, was charged with second-degree murder, with lesser charges for five other officers. There have been no indictments in the earlier cases.

These follow other recent incidents and controversies, including an April 2014 finding by the U.S. Department of Justice (DOJ), following a two-year investigation, that the Albuquerque, N.M., police department “engages in a pattern or practice of use of excessive force, including deadly force, in violation of the Fourth Amendment,” and a similar DOJ finding in December 2014 with regard to the Cleveland police department. In March 2015, the DOJ also issued a report detailing a pattern of “clear racial disparities” and “discriminatory intent” on the part of the Ferguson, Mo., police department.

As the Washington Post reported in July 2015, a