advice sought

Just over two weeks ago I was at Newington Green bus stop heading back to Haringay. At the stop a middle aged mother was berating a man who she said had tried to talk to her daughter who was around 6 years old. She furious with him, saying that he had tried to touch the girl and that if he had gotten any closer he would be on the floor because she would have battered him. It was a really horrible thing to witness. The man said he was just complimenting the girl for being pretty but he then got really abusive- called the mother a 'bitch' right in front of the little girl. I didn't really know what to do but I made sure he could see I was around in case he did anything worse. We both boarded the bus he tried to make conversation with me- he seemed to know who I was- but I was quite freaked out by seeing the incident and didn't fancy talking to him.

The following week around noon I am at Manor House about to get down the steps to the tube and I see the same man. He is locked in an argument with two women who are trying to get away from him. He is saying something about how they should behave when someone approaches them or something like that. I didn't hang around because I needed to get to the airport but seeing him again really freaked me out. I was out of the country for a week but it took me about 3 days to not think about him. He just radiated creepiness. I consoled myself that it was quite possible that I would never see him again.

This morning I boarded the 141 bus at Manor House and he got on. I tried to stay calm, not least for my daughter who I was taking to school. But then he started to try to talk to her saying 'your dad is a famous journalist' but not in a very friendly way. As a parent you can have a sense as to who is genuinely friendly and who is not. He then started talking, sort of to himself, about how 'he hadn't done it' and something about prison. He is also using really bad language. My daughter is clutching my hand and really uncomfortable. I manage to turn my phone on an take some photos of him. 

He gets off at Newington Green. Since this morning I cannot take the sick taste of my mouth. I just have a bad feeling about him. 

So the reason I am posting this is for advice- ideally from parents-about how to process and think about all this. I could post his photo but I don't know what the protocol is around that. Right now the idea that I might see him every morning, that he might try to talk to my daughter or do anything else just makes me never want to get on a bus again but that is not the answer.  

Does anyone have any helpful advice on how to not let this totally take over my mind because it has at the moment, hence this lengthy post.

Thank you.