State Fire Marshal Roger Johnson said at a news conference that four bodies had been found in the house and firefighters were searching through debris. Johnson, who had earlier said the fire claimed at least six victims, said investigators are not sure if there are more victims.
"We've had mixed reports on whether there are additional people inside," he said. "We would not be surprised to find to find additional victims but at this point we only have four."
Johnson said there was an unusually large number of people of living in the house, but he would not speculate on how many lived there.
"Flames were rolling out the windows. I could feel the heat coming in through my window. "It was really intense," said Frank Hanrath, who lives across the street.
Michigan City Fire Chief Ralph Martin said officials do not know the identities or the ages of the victims. He said the fire appears to have started in the back of the house, but how it started is not yet clear.
Telephone messages left for the LaPorte County coroner were not immediately returned.