Can you find out if a person has been arreasted?

I would like to know this same thing.

Yes, either pay for a criminal background check, or look at the DOC sites of every state this person has been to (in which he has resided). The latter is free, and you can access state DOC's through...

You would need to do some research in the case index in the various courts in your jurisdiction. Those are generally open to the public.

Who has sued and been sued is public record, although the details about what the suit involved may not be. Most state court systems have a public database that you can search. There is usually a fee...

You call the police. 911 is a good start too.