Charleston, W. Va. ? Eight people, including a woman celebrating her 26th birthday and six young children at a family slumber party, died Saturday when fire tore through a two-story home while they slept, officials and witnesses said.

A seventh child was on life support after the blaze, the deadliest in West Virginia’s capital city in more than 60 years, Charleston Mayor Danny Jones said. The dead children ranged from 18 months to 8.

The cause was under investigation. The fire appeared to have started on the first floor of the home, Charleston Assistant Fire Chief Bob Sharp said. Jones said the home had one working smoke detector on the bottom floor, but it was on a counter and wasn’t properly mounted to a ceiling. Another was found in a basement area but didn’t work.

A children’s picnic table, chairs and an umbrella were overturned in the yard of the home, sitting on a corner in a neighborhood tightly packed with small houses. The outside of the front of the home was blackened by the flames and smoke. Two upstairs windows were shattered and blackened, and what appeared to be an opening for an upstairs air conditioner was stuffed shut with clothes.

Sharp said two of those killed were adults and all of the children who died were younger than 8. Ten people were inside the house at the time of the fire — about 3:30 a.m.