Not to sound harsh, but plenty of people have tried to answer this. Its just not the answer you want.
Keep in mind this is just a message board. Sounds like you might be better served talking to a lawyer if you really want peace of mind as far as what your legal rights are.
I've spoken with lawyers, but they don't know the extent of my rights in this specific situation. All of you guys here, even those who feel my situation is bleak, have been tremendously helpful. I just haven't seen, or been able to find on my end, any laws or statutes stating that I won't be afforded the protection of criminal investigation.
I'd like to again, thank everyone for their support and feedback.
That's not how the law works. You can pursue civil remedies, but as for forcing a criminal investigation, I'm afraid it's not worth the prosecutor's or the police department's time. $4,000 is a lot of money for sure, but I seriously doubt you get anywhere on the criminal side against FedEx.