If someone prank-called the american police or harassed someone through a prank call from overseas would he be charged?
Maybe. It depends on if it constituted a crime. If it did, it would then depend on if there is an extradition treaty between the US and the country of origin and whether or not the local district attorney or federal prosecutor wished to prosecute. A German man who prank-called in a handful of phony bomb threats to local schools in Grand Rapids, Michigan was extradited from Germany to the United States to face charges.
It's always a very bad idea to mess with the police from any country. Most countries have some type of extradition agreement with the USA and even the ones that do not will usually cooperate on some level with many criminal complaints. You really do not want to test any level of immunity you think you may have.
Try it out, & post your results once you are in jail.
Possibly. The best prank calls of all time are those never made.
Yes. Especially since they can easily trace the call.