....
Convicted on "Trumped-up charges". 
...sorry for the bad joke. I couldn't resist.

Seriously, though, I hope it becomes available. My guess is a grenade, maybe?
When I was in the National Guard we do annual training with live weapons and one of them is grenades. So we were training and if 60 grenades get issued, there very damn well have 60 expended grenade pins handed back in.
On that particular day, only 59 was handed in. (I'm using 60 as an example but what happened was one less grenade pin was not accounted for)
It's a big deal. They stood us in formation for hours, while they tried to figure out if it was stolen, being hidden, or if it was a logistical mistake.
After hours and hours of making sure everyone is accounted for while they figured it out, they seemingly solved the problem. What happened was never disclosed.