Head over to his home this evening. Knock on the door.
You: Hey, Frank, how's it going? Got a question for you, my camera picked up you in my backyard last Friday night and I just wanted to come over and ask you what was up?
Him: ...
You: Okay, thanks for the explanation. Take care, buddy.
His response will give you what you need. His body language, his hesitation or straight-forwardness. If he did see the camera, he may have a response already prepared, and you should be able to pick up on that, too. But above all, please make sure to keep us updated, we're all curious now! 🙂