Detectives have worked out how bundles of £20 notes kept turning up year after year on the streets of a struggling mining town in northeast England.
The money was tested for fingerprints and workers at the local post office and bank were interviewed.
But Durham police have said that two good Samaritans with an "emotional connection" to Blackhall Colliery have finally come forward to say they were behind the cash giveaway in an effort to help the poor and disadvantaged.
The unnamed couple began leaving the money in plain sight in 2014, often staying behind to make sure it was picked up, after receiving "unexpected windfalls", police said.
How much money was involved is not clear. Police said locals turned in 13 packages, or around €30,000, to the authorities in the last six years.
Police would hand the money back to the finders after it went unclaimed for a set time. No-one knows how many bundles were never handed in, and the two individuals would not say.
"I'm really pleased we have an answer to this mystery and am glad we can now definitively rule out the money being linked to any crime or a vulnerable person," Detective Constable John Forster said.
"I would like to thank the Good Samaritans for getting in touch and also to the honest residents of Blackhall who have continued to hand the money in."
DC Forster left open the tantalising prospect of more money lying around Blackhall Colliery, a town of fewer than 5,000 whose previous claim to fame was having its beach featured in the climax of the 1971 Michael Caine film "Get Carter".
"We would encourage anyone who may find another bundle to continue to hand it in," DC Forster said.