Legal systems work very differantly.
A guy I used to be stationed with got stationed in Germany. Got nailed by the UCMJ for having "carnal relations" with 2 of his co-workers (one was another guy), at work. At the same time, German police raided his home, and discovered a huge cache of child porn and attempts to seduce children over the internet. The US Military could not use any of that though, due to legal issues.
He still got something like 5 years in a federal pen though. And you can bet word of his "other crimes" met him there.