MINNEAPOLIS (WCCO) – Crews have determined that the cause of a fire that destroyed a South Minneapolis duplex earlier this week was careless smoking.

The fire started at a home on the 2200 block of Garfield Avenue South at around 6 a.m. on Tuesday.

The Minneapolis Arson Unit released their findings that careless smoking was to blame early Thursday morning.

Authorities think there were six people inside the home at the time of the fire. Three residents were sent to the hospital.

One of the victims, a man, was breaking windows and warning people inside the duplex to get out of the burning building. He suffered cuts and burns.

One of the women inside was transported for precautionary reasons. Fire crews found another woman inside on the first floor. She was conscious, but also transported to the hospital for observation.

Two dogs were missing after the fire and it was not known if they died or ran away.