Get over there with a baseball bat. Put the fear in him, force him to talk about the child porn while secretly filming him... Thats what I would do.

If you don't have anything that's sufficient probable cause for the police to get a warrant, you could send the police an anonymous tip, and they may be able to get a search warrant based on that. Anyway, gotta remove your post, as it's not relevant per the pizzagate definition, and also has no source/link.