Seldom has the term "dirty money" been more appropriate.
The discovery of tens of thousands of euros flushed down Geneva toilets has left detectives perplexed.
Bundles of shredded €500 notes were discovered blocking toilets near the safe-deposit room of a branch of the UBS bank, and also in the lavatories of three nearby restaurants.
Prosecutors say they are still to identify who felt flush enough to literally pour money down the drain.
Investigators told the Tribune de Genève newspaper they suspect it may have belonged "to Spanish women who placed it in a safe-deposit box several years ago".
Police have not disclosed the women’s identities and are unsure why they would have wanted to dispose of it. Detectives are attempting to determine whether it was the proceeds of crime or stolen.
A lawyer acting for the women went to police headquarters last month, where he was questioned but provided little information.
He handed over money to pay for repairs to the toilets of the bank and the restaurants, which had to spend thousands of euros getting them unclogged.
But he offered no explanation about why money belonging to his clients, who were seen on CCTV footage at the bank a few months ago, might have ended up in the toilet.
UBS staff were shocked and dismayed when they discovered why the lavatories were blocked in June.
Days later, more shredded notes turned up at nearby restaurants. The staff of a pizzeria where the banknotes caused the toilet to flood took it more lightly.
"We couldn’t stop laughing," an employee said. Staff took photographs showing the floor of the men’s lavatory flooded, and sodden bills, methodically cut up with scissors, in the toilet bowl and the washbasin.
Destroying banknotes is not illegal in Switzerland, which used to have a reputation as a safe haven for ill-gotten gains.
Henri Della Casa, a spokesman for the Geneva prosecutor’s office, said: "There must be something behind this story. That’s why we started an investigation."
He declined to comment further — and UBS also said it would make no statement about the incident at its branch in Rue de la Corraterie in central Geneva.
Some speculate that the money may have been destroyed out of fear of the tax authorities before new legislation comes into force next year requiring Swiss banks to share more information with governments.
The Tribune de Genève said investigators are unclear about whether a man caught on CCTV in one of the restaurants, entering the toilet with his pockets apparently stuffed with wads of banknotes, was acting on behalf of the women.
"Tax evasion is the most likely theory," said the manager of the Café du Centre. "They should have given the money to beggars."