A 61-year-old woman was killed in a fire in Mount Orab early Saturday.Brown County sheriff's deputies said the fire in the 14000 block of Eastwood Road started about 1:43 a.m. Saturday.Deputies identified the victim as Diana Monoskie.Friends told News 5 they saw the Monoskie’s oxygen tank explode inside the home as firefighters were battling the blaze.“At first it started out (it) looked like a little bonfire actually in the middle of nowhere. We usually have little bonfires but by the time we got to the next door neighbors' driveway it was up in flames,” Ricky McBride said. He was one of the witnesses who called 911.Friends said Monoskie lived in the home with her grandson, his pregnant girlfriend and their child.The cause of the fire is under investigation. Damage was estimated at $90,000.