BOISE, Idaho (AP) — Officials in Boise County say they've arrested an 18-year-old volunteer firefighter suspected of igniting a blaze that destroyed one home and is threatening about 100 other residences. Authorities identified the suspect Tuesday as Nathanial Fay Bartholomew. He was arrested on a felony arson charge for allegedly causing the Karney Fire that has so far burned 250 acres in the Robie Creek area of the Boise National Forest. Forest spokesman David Olson says the fire started late Monday afternoon. About a dozen residences were evacuated Monday night while additional homes received evacuation orders Tuesday morning. Sheriff's officials said Bartholomew lives in the area. Investigators say it appears the fire was set some in pine cones and other fuel at the side of a road then spread to a nearby home.