Thousands of Colombians have joined protests in cities across the country to demand the resignation of the country's chief prosecutor, Nestor Humberto Martinez. <br /><br />Protesters at a rally in Bogota could be seen tearing down and then burning a flag outside his office.<br /><br />Some held placards accusing him of corruption. <br /><br />Martinez is a crucial U.S. ally in the war on drugs, however he is accused by his critics of obstructing an investigation linking Colombian politicians and business groups with Brazilian construction firm Odebrecht.
