A fire engulfed a house where 12 people were sleeping in a 20-by-30-foot upstairs apartment without required smoke detectors Tuesday, killing nine, including seven children, and injuring three, officials said.

Police Sgt. Rocky York said authorities were looking for a person for questioning, but the person "is not an arson suspect at this time." An initial investigation turned up "no sign of arson."The fire broke out at 2:24 a.m. and the two-story wood-frame house was engulfed in flames when firefighters arrived, officials said.

A neighbor climbed on top of the burning home from a tree to help the victims, and firefighters plucked the three survivors and the unidentified rescuer from the roof, Joos said.

"Everybody in the neighborhood knew these people and the children. The situation now is obviously gloomy," fire department Greg Joos said.