NEW CASTLE, Pa. — Three mentally disabled brothers have been found dead in a Western Pennsylvania house fire that appears to have been fueled by some kind of flammable liquid in several spots.

That’s why state police and the Lawrence County coroner are treating the deaths of Daniel, Robert and Richard Fombell as homicides — though they haven’t ruled out that one of the brothers may have caused the Thursday morning blaze in Shenango Township. The brothers, all in their 50s, have lived alone since their mother died. State police believe the fire may have started about 5 a.m. when some neighbors smelled smoke, but it wasn’t reported until someone saw flames glowing in the basement about 7:30 a.m.