People hold candles and images of a cross near a police car during a vigil by the NGO Rio de Paz in honor of police officers killed in pacified slums in Rio de Janeiro, Brazil, Monday, March 17, 2014. In recent weeks, several officers from pacification police units, aimed at freeing favelas from drug lords ahead of the World Cup and Olympic games, have been killed in shootings and attacks inside the slums. [Photo/icpress.cn]