Haha, what a silly question...except the guy actually did have a large amount of United States currency in the vehicle. Either that cop is the world's luckiest guesser, or they had some reason to think he had a bunch of cash in his car.
If the DEA really didn't comply with it's legal obligations about returning the money/explaining though, I guess the guy has a pretty strong case to get it all back plus a bit extra.
Not sure why he couldn't just send the bank receipts he already showed the cop to the DEA or whatever. Principle?
I have a lot of questions about this story.