A fire broke out just before noon on Wednesday, in the 3100 block of East Salem in South Bend.
The homeowner left to visit a nearby relative.
He says he was gone for about 15 minutes, when an alarm started going off telling him someone had broken in.
He returned home to find flames shooting out the window.
Three bedrooms in the back of the home were damaged.
Firefighters say smoking material in a waste basket is to blame.
No one was injured during the fire.