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

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.

The statement on Monday by George Reagan Jr., a spokesperson for the Gabriel House ownership, said they were “eternally grateful” to the Fall River fire and police departments for their “heroic response to the fire.” The statement also commended ambulance companies and medical personnel who provided care to the victims.

The owner of Gabriel House assisted living facility has defended its inspection record, saying sprinklers were tested just days before the fire.

The cause of the Gabriel House fire that killed 10 assisted living residentsin Fall River this month is officially “undetermined” because investigators cannot yet say whether the fatal fire was started by the electrical or mechanical failure of an oxygen machine in a resident’s room,

The pair of press briefings comes as several key questions about the fire linger, including the its cause and when and where exactly it started inside the three-story complex.

For weeks at a time, assisted living residents in wheelchairs on the top level of Gabriel House couldn’t leave their floor, trapped by a broken elevator that management wasn’t in any hurry to fix. Because they couldn’t make it downstairs to the communal dining room,

On Saturday, 66-year-old Brenda Cropper’s niece, Priscilla Andrade, visited the memorial for the first time since the fire. She was with her aunt hours before the flames erupted.