Hong long do the feds have to charge you?

It depends on what the investigation is that is going on and causing them to hold up on charging you. There must be a big target out there that they are wanting, far bigger than you. OR, they are no longer interested in messing with your case because it did not turn up any big fish. And, as you know, they have until the statute of limitations runs to file the charges.

With federal funds being largely diverted toward terrorism, the U.S. Attorney's Offices are just as short-staffed and overextended as anyone. The answer regarding your delay could be as simple as that. (Please note that this answer does not constitute legal advice nor does it establish an attorney-client relationship.)

If you assume that the statute of limitations on all federal offenses is five years, that assumption is definitely incorrect. Also, if you are accused of conspiracy or some other ongoing offense, the feds may contend that the statute did not start to run when you believe that it started to run. A third possibility is that you were charged by way of a sealed indictment, although you would have a claim for post-indictment delay if the feds waited so long to inform you of the charges. As a very general rule, speaking as a long-time federal prosecutor, if you still have not been charged 3 1/2 years after your arrest, you probably will not be charged. But there are plenty of exceptions to this rule.