Police in Austria are baffled over how €100,000 in loose banknotes came to be floating down the river Danube.

A young man spotted the cash – in €500 and €100 denominations – and dived into the river to retrieve it, with onlookers thinking he was attempting to commit suicide, Oesterreich newspaper reports, according to Sky News.

Bystanders, concerned for the man’s safety, called the police who arrived at the scene as the man was retrieving the loose notes.

Police are now searching for the rightful owner, and if they can’t find them within one year then the young man will be entitled to it.

Detectives say there is no recent crime they can link it to, and have ruled out money laundering.