13-year-old Tommy McNeil died in the fire. His father, chief Rick McNeil, was critically injured.
He’s being treated at Maine Medical Center in Portland.
Now sergeant Troy Gardner says three people, including a woman, were in the trailer the night of the fire.
Police have interviewed the woman, but won’t identify her or say whether she knew how the fire started.
She was not hurt in the conflagration.
There has been no word yet on a cause of the fire.