Is it possible to prosecute someone for cyber bullying who does not live in the U.S?

Let's say, for example, an individual currently residing in the U.S was a recent victim of cyber bullying. The perpetrator does not live in the U.S or any western country for that matter. How do our courts deal with such cyber criminals? Do they just let them go unstopped to possibly bully other U.S citizens or will they be extradited in the U.S to face charges?