By Amy Woodyatt, CNN
London (CNN)Almost £180 million ($249 million) in cryptocurrency has been seized by London's Metropolitan Police -- the biggest confiscation in the UK, the force said.
The confiscation is thought to be one of the largest globally, the Met Police said, and comes just weeks after police confiscated £114 million ($158 million) of cryptocurrency in June.
The seizures were made by the force's economic crime command, after pursuing intelligence received about the transfer of criminal assets, a press statement said Tuesday.
The seizures formed part of an ongoing investigation into international money laundering.
Cryptocurrency is an all-digital money system made up of "coins" or "tokens" that are controlled by a decentralized ledger.
Police have not specified which cryptocurrency was seized.
A 39-year-old woman was arrested on June 24 on suspicion of money laundering offenses, and was released on bail, police said.
She was interviewed under caution in relation to the latest discovery of nearly £180 million on July 10 and has been released on bail until later this month, the force added.
Detective constable Joe Ryan said this month's seizure was a "significant landmark" in an ongoing operation.
"Less than a month ago we successfully seized £114 million in cryptocurrency. Our investigation since then has been complex and wide-ranging," he said.
"We have worked hard to trace this money and identify the criminality it may be linked to. Today's seizure is another significant landmark in this investigation which will continue for months to come as we hone in on those at the centre of this suspected money laundering operation," Ryan added.
Deputy assistant commissioner Graham McNult added in the statement: "Proceeds of crime are laundered in many different ways. While cash still remains king in the criminal word, as digital platforms develop we're increasingly seeing organised criminals using cryptocurrency to launder their dirty money.
"Whilst some years ago this was fairly unchartered territory, we now have highly trained officers and specialist units working hard in this space to remain one step ahead of those using it for illicit gain."