A demonstrator yells at police officers during a protest outside the Mobil On-The-Run gas and convenience store in Berkeley, Missouri on December 24, 2014. In the latest incident to fuel mounting tensions over a spate of police killings, a black teenager was shot dead by a white officer in Berkeley, Missouri after he allegedly pointed a gun at the officer. The incident took place late December 22nd at a gas station in the town near Ferguson, Missouri where another black teen was shot dead by a white officer last August. St Louis county police chief Jon Belmar said the officer was called to the gas station about a theft and when he arrived two men approached the police car. The suspect then pointed a nine-millimeter pistol at the officer, who drew his own weapon and fired three shots, one fatally striking the suspect. AFP PHOTO / MICHAEL B. THOMAS