I don’t see any reason to assume the money was ill-gotten. He was an old man that probably didn’t trust banks, like my own granddad.
I used to lurk on a metal detecting forum. There was a story about one guy that left his metal-detecting adventures and went to exploring old abandoned houses on the outskirts of town. But still kept up with his metal-detecting friends.
One day he drove up to the Saturday morning breakfast his metal-detecting friends had before going off to the local park or whatever. He motioned to his best friend in the crowd to come look at his car. He opened up the trunk, and inside were several old suitcases. He opened one up and it was full of cash - the other suitcases were stuffed as well that he had found in an abandoned house. Then he drove off, never to be seen again.
Like most “treasure” stories - who knows. But fun to think about. Other than perhaps the house isn’t really abandoned, etc.!
I was just speaking with a friend that made the trip to his recently passed away father-in-law’s house - the man was notorius for hiding money. In the back yard in found several buried ammo cans. All empty! (Why bury empty ones back? I suppose to keep the hole open?). But he said his heart was racing after he detected them, dug and hit metal, etc.!!
And 4 hubcaps all in a row spaced 2 feet apart. But nothing underneath them. Weird. They did find some cash tucked in behind some of the electrical outlet covers!