I'm watching "It Takes a Thief," which is a show where these two guys break into a house, then show how to secure it.
Right after they broke in, the first thing the family did was completely WRONG! When you walk into your house and see stuff thrown everywhere, stop, turn around, and the get hell out of the house. There's no saying that the intruder isn't still there.
Get out of the house and call the cops. Don't explore, leave.