Dozens of heavily armed commandos could be seen Thursday frisking residents and going house to house in the Mare complex of slumsElite special forces raided a slum in Rio de Janeiro Thursday after officers providing security at the Olympics made a wrong turn and encountered gunfire. One police officer was shot in the head, and was recovering at a local hospital. The officers from Brazil's national security force were using a GPS device to navigate unfamiliar streets when they took a wrong turn off a highway leading to Rio's international airport. Their truck was sprayed with bullets, and one officer,...