I think the law sucks! While the right thing would have been to give the money to authorities, finding something is not a crime in this country! The guy may be stupid, but the law is a lot stupider.
That being said, I would roll around in it for a few hours and dream golden dreams. Then I would turn it into the police.
I found a wad of 20s that could choke a horse once, outside a bank. Yes, I thought about keeping it for a minute or 2, but turned it into the bank and told them I had found it outside. The guy who lost it did come back soon afterwards (the teller told me on a later day). It was his cash for an upcoming and long overdue vacation, so not like it was his life's savings. Still, I felt a lot better for not keeping it and that the rightful owner was found.
But 1/4 mill? Probably drug money if it was not reported within hours of being lost. And another bagman is feeding the fishes.