Officials determined a deadly New York City fire that killed 12 on Thursday, December 28, was caused by a child playing with a stove burner. The New York City Fire Department posted video on Friday showing the inside of the building after the fire.The mother of the child who started the fire fled from the building with her two children but failed to close the door behind her, officials said. The stairwell acted as a chimney, spreading the fire quickly, officials said.Firefighters distributed fire education materials on Friday, and officials distributed on social media information about the Juvenile Fire-Setters Intervention Program. Credit: FDNY via Storyful