Recent controversial killings by US police:

March 2014: James Boyd, an unarmed homeless man camping in Alberquerque, is shot dead by two officers. Video of the incident leads prosecutors to say the officers acted with “deliberate intention” and they are charged.

July 2014: Eric Garner, an asthma sufferer, is stopped by police in New York and placed in a chokehold after refusing to be handcuffed. He dies despite repeatedly telling officers he cannot breathe. No police are charged.

August 2014: Michael Brown, an unarmed 18-year-old, is shot dead by Officer Darren Wilson in Ferguson, Missouri. The shooting leads to protests, first in Ferguson and later nationwide. A grand jury decides not to charge Darren Wilson.

November 2014: Tamir Rice, a 12-year-old boy, is shot dead in a playground by Cleveland police after a local resident reports he is pointing a gun at passers by. The gun turns out to be a toy. A grand jury will decide whether police will face charges.

December 2014: Jerame Reid, 36, is shot dead during a routine traffic stop in New Jersey. An officer claims Jerame Reid was reaching for a gun, but video footage seems to suggest he was attempting to step out of the car, hands raised.

April 2015: Walter Lamer Scott, 50, is shot eight times in South Carolina as he runs away from Officer Michael Slager. Walter Scott dies at the scene. The shooting is captured on video and Michael Slager is charged with murder.