Would law enforcement know if that money was being used, because they have serial numbers?
With that volume of cash, you’d assume they had the serials (or at least some of them) but you never know.
The other side of me wonders if there was an actual robbery - or was this some way to explain away a lack of cash somewhere. Bank heists don’t go unsolved - robbers aren’t that bright or able to keep the cash out of sight.
Must have watched too many Benecek episodes, where the twist was that the motive and crime wasn’t what it seemed.
If they were laundered in some way, those physical dollars may not even be in the US to track.