Investigators may never know for certain what sparked the fire on the left side of the U-shaped assisted living facility.

Investigators say a fire that killed 10 people at a Massachusetts assisted-living facility was likely caused by smoking or an oxygen machine's electrical problem.

The deadly fire at an assisted-living facility in Fall River, Massachusetts, was accidental, but the cause is classified as undetermined.

The Massachusetts State Fire Marshal revealed the possible causes of the fire that killed 10 people at an assisted living facility in Fall River.

Investigators reveal 2 possible causes of deadly fire at Fall River assisted-living home Investigators on Tuesday revealed new evidence linked to a raging fire that tore through an assisted-living facility in Fall River earlier this month, killing 10 people and leaving dozens of others hospitalized.

An investigation into the source of the fatal fire at a Massachusetts assisted living facility last week classified the cause as "undetermined," though officials believe it was an accidental ignition

A survivor of the deadly fire at the Gabriel House assisted living home in Fall, River Massachusetts is now suing the owner.

Ten people have died after a Massachusetts assisted living facility caught fire Sunday night, making elderly residents rush to their windows to scream and beg for help as smoke filled the hallways.

All 273 assisted living facilities in Massachusetts will be required to send a letter to all residents and families detailing fire safety protocols.