Calls to 911 reporting a fire at an assisted-living facility in Fall River, Massachusetts, began coming in shortly after 9:30 p.m. Sunday, marking the start of a prolonged emergency response to rescue the roughly 70 people who lived there,

Local and state fire investigators are working to identify the origin and cause of the 5-alarm at Gabriel House on Oliver Street, officials said.

River Fire Chief Jeffrey Bacon deferred all questions about the fire investigation to the Massachusetts Department of Fire Services.