It Was Just A "Mistake"
Initially I signed on as a teacher looking for signs and strategies to deal with high school-age students. I am now seeing some of the behaviours I was afraid of in my own son, now 13.
This weekend we were invited to a family friend's cottage. They gave him several gifts, but when we returned home, it appears as if he may have stolen from them. Specifically, the boys (adults and children) went out fishing. My son borrowed a fishing lure from our host and caught a nice fish with it. The next day the lure was in his tackle box. When confronted he denied stealing it and claimed it must have been a mix-up. Maybe he put his in our host's tackle box and kept the host's.
We made him call the owner a report the "mistake" and make arrangements to make the exchange the next time we were in town. Despite all opportunities to confess his wrongdoing he maintains that he is innocent. I don't believe it. What do I do next?
You've done all you need to do (i.e., had your son call the owner with plans to return the item). I doubt that you will get a confession out of your son. He's probably embarrassed about getting caught and wants to save face at this point.
You're probably right - he took the lure - but if you have no evidence that he did this on purpose, then you should not issue a consequence for "stealing" - or "lying."
I think he learned something from the experience.