It's not guaranteed they won't pay the peon. There's just a process.
It seems like a weird process because everything in the legal world is framed in terms of adversaries, people trying to game the system, official processes that have to be followed, and delays. And for all I know, it will lead to whoever ratted him out getting the shaft. But there's a big difference between "It's more complicated than bebopping on down to your FBI office and getting handed a check" and "They're definitely going to shaft him."