Story time?
They finally decided not to follow-through on the prosecution for it. I guess someone eventually realized that:
a) It was a real bank note, not a forgery
b) It wasn't US currency as they had believed, but a note from Zimbabwe:
https://www.banknoteworld.com/zimbabwe-currency/100-trillion...
I'm struggling to imagine multiple professional law enforcement staff closely examining it and not noticing that it makes no claims to be US currency.