A protester throws back a smoke bomb while clashing with police in Ferguson, Missouri August 13, 2014. Police in Ferguson fired several rounds of tear gas to disperse protesters late on Wednesday, on the fourth night of demonstrations over the fatal shooting last weekend of an unarmed black teenager Michael Brown, 18, by a police officer on Saturday after what police said was a struggle with a gun in a police car. A witness in the case told local media that Brown had raised his arms to police to show that he was unarmed before being killed. REUTERS/Mario Anzuoni (UNITED STATES - Tags: CRIME LAW CIVIL UNREST)