Ok so I'm on the train and I swear I am sitting right behind a pedophile and I'm pissed. He walks onto the train with this little girl, probably around 8years old and I just knew he was a creep from how close he walked behind her. It just wasn't normal, I mean his groin was just way too close to her face and he was holding on to her too tightly. I'm at a certain part of the train at the end and there is this weird corner, anyway he sits her in the corner and sits close to her and wraps his arms around her tightly. She is just playing her games on a gameboy or something and every once in a while he rubs his face against her hood and will hold her tighter. And he would touch his lips in a nervous creepy way. A couple times he looked around as if to see if people were watching and he would look at me and I would stare at him with the nastiest look. I could be wrong about him, I usually try not to judge but this guy just disgusts me. What can I do?