Homeowner Charles DeYoung called 911 at 8:41 p.m., saying that a plane had hit his house, fallen to the ground and then hit a tree, Sheriff Gary Ringhofer said at a press conference early Wednesday.
DeYoung was the only person home at the time; he was not injured.
Names of the victims were not immediately released. Ringhofer said all were male and appeared to be adults.
The crash site is in a rural area about a mile east of Owatonna and about 9 miles from the Owatonna's Degner Regional Airport. The sheriff would not say where the victims were from, where they were flying to or where they had taken off from.
There was no indication that a distress call was placed before the accident, he said. The single-engine plane broke apart when it crashed.
``The scene covers quite a wide area,'' the sheriff said.
Owatonna Fire Chief Mike Johnson said the plane did not burn.
``The aircraft was completely destroyed in the crash,'' he said. The house had damage to its roof.
A neighbor said she heard the plane crash into the house but didn't know what had happened.
``All I know is that they are all dead,'' said Coleen Thompson, who lives nearby. ``When it hit, it sounded like thunder outside.''
Investigators from the Federal Aviation Administration and the National Transportation Safety Board were assisting in the investigation.