The U.S. has an extradition treaty with Peru:
http://www.oas.org/juridico/MLA/en/traites/en_traites-ext-usa-per.pdf.
Whether extradition is possible, however, depends in part on the laws of Peru regarding that conduct, and of course I'm not too familiar with the laws of Peru.

Also, it would have taken some time to work out the extradition, even assuming that the feds had any clue where Joran was at the time.
I'm a little confused by this Complaint. Where's the extortion/fraud?
This looks like something that was filed because the feds wanted to file "something" against him but didn't have the facts they needed to really charge him with what they wanted to charge him with. I don't think they would have filed this on May 10. I think they were waiting for something more. Like the location of Natalie's body.