A 15-year-old boy remains in custody today in connection with a 776-acre wildfire that has destroyed at least one home in El Dorado County. Fire officials say the blaze is threatening 30 other homes and nearby residents have been ordered to evacuate. The fire is 50% contained and is burning through dry trees and brush about 40 miles east of Sacramento. Four people were reported injured. Three were felled by heat exhaustion, the fourth by a medical problem.