Village residents who handed in bundles of cash which were mysteriously left on the streets have been praised for their honesty.
Packets of notes, usually amounting to £2,000, have turned up in Blackhall Colliery in County Durham on at least 12 occasions since 2014.
Police have been unable to determine where the money came from.
The chair of the local parish council said it was "heart-warming" that locals had such honesty and integrity.
The money has always been left in public places, often on the pavement, giving rise to the belief it was meant to be found.
Det Con John Forster, of Durham Police, said: "We've had the theory that it could be a lottery winner who has decided to pay something back to their local community, but the truth is we don't know.
"You have to imagine that potentially money's been found that hasn't been handed in to us - we might never know the amount of that.
"But I'm just thinking how great it is that there are so many honest people in this village, their first instinct was to get straight to the police station.
"Some of them are shaking when they come in, they just want it to get back to the person who may have lost it."
Gaynor Crute, chair of Monk Hesleden Parish Council said: "There's so much negativity and bad press so when you have something like this it is obviously heart-warming to know the people you live with, your neighbours, have so much honesty and integrity."