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.

According to Fire Chief Jeffrey Bacon, the blaze started in a room on the second floor on the east side of the Gabriel House building, but details about the exact origin and cause are under investigation.

Authorities identified the victim as Brenda Cropper, 66. She had been hospitalized in critical condition since Sunday’s fire, which was the deadliest blaze in Massachusetts since 1984.