The FBI and ATF are investigating an explosion that leveled a Dayton house and caused heavy damage to the house next door Monday morning. Demolition of the heavily damaged house next door began Monday night. The explosion happened in the 500 block of Brooklyn Avenue near the intersection of Kammer Avenue on the city’s west side. The house was vacant, but two people on the street suffered minor injuries from flying debris. Fire officials say more than 40 structures including homes and garages were damaged.