Police in Austria are investigating how bank notes worth tens of thousands of euros ended up in the River Danube.

The notes were found floating down the river in Vienna on Saturday, leading one passer-by to jump in and salvage the money.

A police spokesman told the BBC that the recovered money was worth some €100,000 (£72,000; $108,000).

The origin of the money is murky. Photo: Vienna Police

Police said there were no crimes were recorded in the area and that it was not clear where the money originated.

Reports in Austria said officers had first believed the money - made up of €500 and €100 notes - was counterfeit, but they now believe the notes to be genuine.

It is not clear if the money was put in the water as part of a laundering operation. Photo: Vienna Police

They were first alerted when bystanders spotted a boy in the river on Saturday. Fearing he was attempting suicide, they called police, only to find he was trying to retrieve the money.

Anyone who finds money and hands it to police in Austria is entitled to keep between 5% and 10% of the total.

The boy, whose name has not been released, netted thousands of euros from the Danube. Photo: Vienna Police

But if the owner is not found within a year, the whole sum will be handed to the boy.