Thornton fire investigators are trying to determine the cause of an apartment fire that killed one person and left 21 families homeless.
The blaze broke out in the Summit Apartments in Thornton near I-25 and 88th Avenue, just north of Denver.
Officials say it started around 3:00 this morning. One man, who has was killed when part of the roof collapsed, and prevented firefighters from entering the building. The man has not been identified. It took most of the morning to get the flames under control.
There is no estimate on the cost of the damages at this point, but, fire officials say the building is a complete loss.