Around €6.5 million worth of cryptocurrency has been seized by gardaí investigating money laundering and “darknet markets”.
Three people were also arrested during a raid involving armed gardaí at a home in north Co Dublin.
During the course of the search, investigators seized “substantial assets”, including Bitcoin and Monero cryptocurrencies with a current market value of approximately €6.5 million.
They also seized luxury-branded watches worth in excess of €120,000 and two high-powered vehicles valued in the region of €220,000.
Two men, aged 23 and 49, were arrested on suspicion of “enhancing the capability of a criminal organisation to commit a serious offence”.
A 32-year-old woman was also arrested on suspicion of alleged offences under money laundering and terrorism financing legislation.
The woman and the 49-year-old man have since been released from custody pending the submission of a file to the Director of Public Prosecutions.
The 23-year-old man remained in Garda custody on Thursday morning.
Detectives from the Garda National Cyber Crime Bureau (GNCCB) were assisted by the armed support unit during the raid.
The GNCCB said it shut down the darknet at the centre of the operation.
A darknet is an encrypted part of the internet that is not normally visible to the general public without specific software, and is often used for illegal purposes.
Detective Superintendent Michael Mullen of the GNCCB said: “The arrests of the three individuals and the assets seized are the result of a highly complex investigation into criminal Darknet Marketplace activities by specialist investigators attached to the Garda National Cyber Crime Bureau.
“These Law Enforcement actions demonstrate Irelands continued determination that this jurisdiction is not a safe place for persons involved in any form of criminality and the determination of An Garda Siochana to prevent those involved in criminality of benefitting financially from same, irrespective of what form such profits takes.
“I would also like to reassure the public that this darknet market, where illegal good and services were for sale, is no longer in operation.”