US civil rights activists embarked Saturday on a seven-day march to demand sweeping police reforms and denounce a grand jury’s decision not to indict a white officer who shot dead an unarmed black teenager.The National Association for the Advancement of Colored People (NAACP) organized the 120-mile (192-kilometer) “Journey for Justice,” heading from the St Louis suburb of Ferguson, where Michael Brown was killed, to Missouri state capital Jefferson City. A core group of around 100 marchers, hope to attract thousands in their demands for the sacking of the Ferguson police chief.