A secret WhatsApp group was used to move hundreds of millions of euros around the world. The group helped clients send money across borders.
This money was used to fund organised crime and extremist groups. The investigation found no paper trail for these transactions.
The group chat was called "Traders of Greater Europe" and had 532 members.
European broadcasters discovered the scheme through their investigation.
The method allowed criminals to move money without being easily tracked by authorities.
This highlights a new way criminals are using technology to hide their activities.
Authorities are now looking into how to stop these digital money laundering methods.
The scale of the money moved suggests a significant operation.