The cause of a deadly fire​ at the Gabriel House assisted living home in Fall River, Massachusetts has been narrowed to two possibilities.

FALL RIVER, Mass. (AP) — The cause of a fire at a Massachusetts assisted-living facility that left 10 people dead remains undetermined for now as officials investigate whether smoking materials and an issue with a medical oxygen machine may have been factors, officials said Tuesday.

More information on the cause of the deadly Fall River fire at Gabriel House on July 13 was released Tuesday. During a press conference Tuesday afternoon, officials said evidence narrowed the cause down to two possibilities, either an electrical or mechanical failure of an oxygen concentrator or the improper use or disposal of smoking materials.