A woman died Wednesday shortly after firefighters found her on the floor of her Miami home as it filled with smoke.

What caused the Liberty City fire and her death was still under investigation, but Miami firefighters believe cigarette butts found near her recliner played a part.

The woman, 56, lived in the back unit of a duplex in the 6300 block of Northwest 17th Avenue. Her name was not released Wednesday.

Shortly after midnight, a family of six in the front unit heard banging in the back, Miami Fire-Rescue spokesman Lt. Ignatius Carroll said. A couple hours later, they heard an alarm, Carroll said, but it stopped.

Hours later, the family heard the alarm again and a commotion, Carroll said. One person looked around outside but didn’t see anything suspicious. About 9 a.m., a man and woman inside the home when they felt their eyes burning and called 911.

When firefighters arrived, the family told firefighters that they thought smoke was coming from the back unit.

Firefighters found heavy smoke the woman unresponsive on the bedroom floor. Investigators believe she had trouble walking because they found a walker in her room.

Paramedics took her to Jackson Memorial Hospital’s Ryder Trauma Center, where she died.