REPORTED BY KALAHAN DENG
These are just some of the 623 people killed by US police officers in 2014
Michael Brown, 18: Shot twice in the head in Ferguson
Dontre Hamilton, 41: Shot 14 times in a park in Milwaukee
Eric Garner, 43: Died after being put in a chokehold by a New York police officer
Tamir Rice, 12: Gunned down in Cleveland after officers mistook his toy gun for a real one
Rumain Brisbon, 34: Killed by a Phoenix police officer who mistook pill bottle for a weapon
Walter Scott, 50: Gunned down whilst fleeing from a police officer at a traffic stop altercation.
Freddie Gray, 25: Arrested after running from a police officer, Freddie Gray died after an unbuckled journey in a police van that prosecutors have said was deliberately reckless.