You broke the rules, but not the type that would cause you to get into legal trouble; you broke the first rule of checked baggage, and that is this:
Never (and I mean
NEVER) place anything in a checked suitcase in the USA that you care about. Never check valuables of any kind.
Sorry you had to learn that lesson by personal experience.
Someone stole your pills, either a TSA thug or an airline thug.