The State Fire Marshal's Office is calling a Jefferson County house explosion incendiary.
A man was spotted at the scene of a home explosion at W7496 Manske Road in Waterloo Township 5 minutes before Monday's fire and explosion, according to investigators.
"There obviously is a vehicle, a person of interest, that we are trying to obtain additional information about at this point," said Chief Deputy Jeffrey Parker, of the Jefferson County Sheriff's Office.
Seven fire departments were called to assist in fighting the fire.
A neighbor who reported the fire said an explosion could be heard and felt. Some of the debris from the house ended up in the neighbor's yard.
A family lives in the home, but no one was at home at the time of the fire.
Investigators are following-up on tips and asking the public for more information.
Anyone with information is asked to call the Jefferson County Sheriff’s Office at 920-674-7310.
Anonymous tips can be call in to the Wisconsin Arson Hotline at 800-362-3005.