Fire officials have identified the 5-year-old Capitol Heights girl killed in a house fire that also critically injured her brother and 15-year-old uncle as Jade Buffaloe, authorities said Thursday.

Buffaloe was pronounced dead several hours after the blaze that consumed her family's two-story, brick duplex in the 6300 block of Carrington Court Wednesday afternoon. When firefighters arrived just after 4:30 p.m., she was trapped in the upstairs of the home along with her 15-year-old uncle, authorities have said. Her 24-year-old father was severely burned and in the front yard, authorities have said.

Firefighters were able to pull the children from the home, but neither was conscious or had a pulse, authorities have said. They and the 24-year-old were taken to the hospital, where Buffaloe was later pronounced dead. The 15-year-old and the 24-year-old remained hospitalized in critical condition Thursday afternoon, authorities said.

Early Thursday, fire officials announced the blaze was accidental, sparked by an overloaded electrical circuit. Mark Brady, a spokesman for the Prince George's County Fire/EMS Department, said the family had a window air conditioning unit plugged into an extension cord, which was plugged into a power strip, which was plugged into the wall. He said the air conditioning unit bore a warning that it should only be plugged into the wall because of the amount of power it would need to draw.

“You cannot use those residential extension cords, which are pretty thin,” Brady said. “When you pull that much electricity through them, they will overheat and start a fire.”

Brady said firefighters canvassed the neighborhood Thursday and found that it was a fairly common practice among residents to plug window air conditioning units into power strips or extension cords. He said firefighters often gave residents a choice: unplug your air conditioner or unplug your computer.

“It’s eventually going to overheat, and it’s eventually going to cause a fire,” Brady said.

Brady said the 24-year-old, 15-year-old and Buffaloe lived in the home where the fire occurred, along with the mother of the 24-year-old and 15-year-old. The mother, 52, returned home as firefighters were battling the blaze and had to be taken to the hospital for treatment of emotional distress, Brady said.

It remains unclear why no one was able to escape the blaze unharmed. Though the window unit was in the living room — and the fire possibly blocked the main entrance — the home had multiple windows and a rear exit, Brady said. The home also had two working smoke alarms which went off, Brady said. He said investigators had not yet been able to talk to the 24-year-old or 15-year-old to determine precisely what happened.

This post has been updated.