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

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 fire that killed 10 people at a Massachusetts assisted-living facility was unintentionally caused by either someone smoking or an electrical issue with an oxygen machine, investigators said Tuesday.

Elderly residents – some in wheelchairs and some dependent on oxygen tanks – were blinded by deadly smoke as they tried to escape an assisted-living facility in Fall River, Massachusetts, which caught fire Sunday evening.

After a fire set an independent and assisted-living facility in Fall River, MA, ablaze, one resident filed a civil lawsuit against the company that manages the complex.

The Bristol County District Attorney’s Office released the previously withheld name of one of the 10 victims killed in the July 13 fire.

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.

Brenda Cropper, 66, died at a hospital after being in critical condition all week after the fire erupted on Sunday, officials said.

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