A fire killed four people early Sunday in a two-story house where about a dozen people lived in makeshift rooms, some of them bedding down in closets, the state fire marshal said.

The cause of the fire had not been determined.

Authorities did not expect to find more bodies, Fire Marshal Roger Johnson said.

Witnesses reported that several people fled the house "in rapid fashion" before police and fire officials arrived and had not returned, he said.

"We don't know why they left, why they did not want to stay and why they did not want to address any questions we may have," Johnson said.

Immigration officials had been to the scene, Deputy Fire Chief Chuck Greise said.

There was no indication of foul play but it had not been ruled out, and a task force formed to investigate the fire included agents of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, state Fire Marshal Roger Johnson said.

City Fire Chief Ralph Martin said that when fire crews arrived the rear of the home already was fully engulfed in flames and within minutes the fire had spread through the entire house. He said the fire appeared to have traveled through the walls or ceilings. Crews needed three hours to extinguish the blaze.

Johnson said he did not know how many people were there when the fire started but he said there were "an abnormal number of sleeping areas in the house." Mattresses were found inside closets and there appeared to be some makeshift rooms with spots for about 12 to 15 people to sleep, he said.

Neighbor Holly Hanrath said the house had been up for sale and she and her husband Frank had been inside about two weeks ago. She said it had been subdivided into rooms with plywood sheeting and there were mattresses on the kitchen floor. The couple said the wiring and plumbing were old and they could smell gas near the stove.

The Hanraths live across the street. "I could feel the heat coming in through my window. It was really intense," Frank Hanrath said.

Neighbor Tawny Anderson said firefighters hosed down her house and the one next to it to prevent the flames from spreading. Anderson said she moved into the neighborhood only six weeks ago and did not know the people in the burned house.

Officials did not know the victims' identities or ages. There was no immediate response to calls seeking comment from the LaPorte County coroner's office.

Michigan City is in northwestern Indiana, about 35 miles east of Chicago.