The puzzle of the abandoned accordion has been solved. We received an email late last night which said, "In case you were wondering how that mysterious accordion got in front of your house, I dropped it off earlier today. My friend at school didn't know what he should do with it and he couldn't throw it away.....so I thought of you hahaha. I hope you like it. It could use a bit of a touch-up though, but at least it's not in the trash ."
Our godson was the culprit. I'm impressed that he can spell accordion correctly. :^)