Hundreds of people swept through the Magnificent Mile and other parts of downtown Chicago early Monday, smashing windows, looting premium stores, clashing with police, and at one point exchanging gunfire with officers, authorities said. Officials said it was not clear what sparked the unrest. However, hours earlier, dozens of people faced off with officers on a police line after officers shot and wounded a suspect in the Englewood neighborhood on the city’s South Side, raising tensions in the city. The angry group falsely believed that police had shot and wounded a child, reports said. Police made several arrests through the night and recovered at least one gun, officials said. By 3 a.m. police appeared to have the situation under control, local reports said.