GARDAI swooped on a property in a rural town and arrested a young man as part of a huge international probe into a black market website selling heroin and cocaine.
The arrest of the suspect was in connection with a US-based investigation into Silk Road, a website where illegal drugs can be purchased with the digital currency, bitcoin.
As a result of a request from the US authorities for help under a mutual assistance agreement, a joint operation was set up involving the garda national fraud bureau and the garda national drugs unit.
This culminated in a swoop by officers on the home of a 25-year-old suspect at Johnstown Court, Kilpedder, Co Wicklow, on Friday.
Gardai seized computers, hard drives, memory sticks and a small quantity of what is believed to be drugs during a search of the house.
All of the seized items were taken away for detailed forensic examination.
Two other men were also arrested at the weekend -- one in Australia and another in the US.
The 25-year-old man arrested in Kilpedder is due to appear at Bray court on January 13, on a charge of obstruction under the Criminal Justice (Mutual Assistance) Act 2008.
The charges followed the arrest in October of alleged Silk Road founder Ross Ulbricht, who is known online as 'Dread Pirate Roberts'.
US authorities shut down Silk Road at the time of Ulbricht's arrest -- though last month a new marketplace, carrying the same name and appearance -- appeared online.
News of the arrest comes as it emerged that Irish criminals are buying an arsenal of deadly high-powered guns and drugs on the "dark internet".
The Department of Justice last night confirmed that so-called "dark net" sites -- anonymous and virtually untraceable global networks -- are being used in this country to supply and source illegal drugs and firearms.
Various dark internet websites contain thousands of listings for high-grade cocaine, speed, a range of synthetic drugs and heroin.
"Possession or supply of illegal drugs or unlicensed firearms carry heavy penalties irrespective of the source," a spokesman said.
The "dark net" refers to the criminal part of the internet which is not normally visible on search engines such as Google.