Arson investigators were at the scene of a wildfire near Los Angeles that exploded in size Thursday to more than 1,700 acres and destroyed at least two homes, authorities said. Three people had been arrested in connection with the fast-moving Colby fire, but Glendora police declined to provide further information. L.A. County fire Inspector Scott Miller said the cause of the fire, reported shortly before 6 a.m., was still under investigation, but said arson investigators were on hand and working with Glendora police. […] Nathan Judy, a spokesman for the U.S. Forest Service, said at about 10 a.m. that more...