OP, leave your post exactly the way it is. Best not to put anything on the internet that might be incriminating, especially if the officer(s) let you walk and even more so if you were actually charged with a crime.
As far as a missing 9mm round is concerned, what the heck are you worried about? Are you worried that the round might be used to kill somebody, your fingerprint will be on it, and you might be found culpable? Jesus, looks like I better not give any ammo to anybody ever again. Wouldn't the rifling marks on the bullet be more telling than any fingerprints on a spent cartridge case?
Let me know what you are worried about and I'll let you know if you are just being paranoid or if you are right to worry.
Fabs, sometime I think you're either too nice or naive for your own good. The op in question is trying to jerk the board off OR has serious mental issues .