Eight people, including a woman celebrating her 26th birthday and six young children who stayed over for a family party, died when fire tore through a house while they slept.
A seventh child is 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 cause is under investigation. The fire appeared to have started on the first floor of the home, Charleston assistant fire chief Bob Sharp said. Mr Jones said the home had no functioning smoke detectors; one was found in a cabinet, but it did not work.
A children's picnic table, chairs and an umbrella were overturned in the garden of the home, sitting on a corner in a neighbourhood 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.
Mr Sharp said two of those killed were adults and all of the children who died were younger than eight. Ten people were inside the house at the time of the fire - at about 3.30am - and all were related.
Roxie Means and her 14-year-old daughter, Cassie, said they attended a birthday party on Friday for Lisa Carter, a hotel worker whose 26th birthday was on Saturday. A manager at the Holiday Inn Express Charleston Civic Centre said he was told that Ms Carter had been killed.
Ms Carter and her two children were staying with her sister at the home, Ms Means said. People started arriving for the party at around 2pm on Friday and it started outside an hour later. "They were nice people drinking a glass of wine," Ms Means said. "They weren't drunk. They weren't overdoing anything."
Cassie said she got to know Ms Carter and played with her children regularly. Ms Carter told her that she was planning to get married in June and move to Pittsburgh to start a new chapter in her life. Cassie said she noticed lit candles inside the home when she attended the party. Hours later, the only adult survivor was smoking a cigarette outside, noticed the fire and came running to Ms Means's home and started "beating down the door", Ms Means said.
The home was engulfed in flames when firefighters arrived. When they went inside, they immediately came across five victims and "started realising there were a lot of people in this house, a lot of children". Mr Sharp said it was the deadliest fire in the city since seven firefighters perished in while battling a fire at a Woolworth department store in 1949. "You can imagine how traumatising that is to us and shocking to the community in general," he said.
Police later named some of the victims as Alisha Carter-Camp, who was celebrating her 26th birthday; three-year-olds Jeremiah Camp and Elijah Scott; Keahna Camp, eight, Emanuel Jones, 18 months, and Alex Seal, an adult whose age was not given.