Besides, if he's physically in Peru but using telephones, etc., to commit fraud and extortion against persons in the USA, the USA has every right to go after him. If some foreigner were committing extortion against you, you would say the same thing.
No jurisdiction. Extortion from a phone in Peru isn’t U.S. jurisdiction. The fascist United States has long used the “any connection to American soil is American jurisdiction” for decades. For the record, the Allies didn’t even have jurisdiction to execute Nazi officials for “crimes” since 1) everything they did was perfectly legal and 2) again no jurisdiction.
You want to shoot the NDSAP leadership as an act of war, fine, , but dont pretend there was some sort of legal basis. Ex post facto law, no jurisdiction, sovereign state actors, so many reasons to not have trials! There is no crime here for American courts to deal with. The Peruvians sure.