An Internet site that let users change real money digital currency has been shut the USA's Department Justice (DOJ). The site, called Liberty Reserve.com, was a place criminals the world to launder money. Money laundering is when "dirty cash" drugs, robberies, etc. is changed into "clean money" that the crime gangs can use. Criminals laundered (changed) more than $6 billion using Liberty Reserve. Police are investigating locations 17 countries and have taken away dozens computers and hard disk drives. They hope these can help them find more about how Liberty Reserve operated. The DOJ says this is the largest case of money laundering ever. Liberty Reserve.com looked like a website people to change dollars, euro and other currencies digital money. Owners other digital cash sites say this system makes it easier and cheaper to transfer money around the world. However, the DOJ says Liberty Reserve was started the main purpose laundering money. It says the website was designed, "to help criminals conduct illegal transactions and launder the proceeds their crimes". It added the site was, "a financial hub the cyber crime world" that allowed credit card theft, investment fraud, hacking, child pornography and drug trafficking. Many honest people who used Liberty Reserve are now worried they have lost their money.