Mail Theft

This evening my dad discovered that we have been the victim of mail theft- several bills he had put in the box Sunday evening had apparently been removed- then opened, and placed in someone else's mailbox! The other mailbox happened to belong to members of our church, who we saw this evening. Along with our mail were opened bills from various other people, though not on our road. Not sure if anything was removed or not- though the bills are apparently intact; dad's going to get the stolen mail back tommorow. A very strange case- not so much that the mail was stolen, but the fact that it was stuck in another mailbox instead of simply being discarded. I can't think of any reason for it- intimidation, an attack of guilt, or just mere stupidity? At any rate, it's very odd, and a bit unnerving.