Dutch tax enforcers with the Netherlands’ Fiscal Intelligence and Investigation Services (FIOD) arrested two men Monday for allegedly laundering millions of euros in cryptocurrency, according to a joint statement by the Joint Chiefs of Global Tax Enforcement (J5).

FIOD arrested the Dutch nationals in separate crypto tax evasion investigations, recovering about 260,000 in unnamed cryptocurrencies and more than 6.6 pounds of gold. Credit and debit cards holding crypto and euros were also seized, among other items.

One of the suspects is alleged to have used the defunct bitcoin mixing service Bestmixer.io.

FIOD has stepped up its crypto policing recently. Working with tax authorities from the U.K., U.S., Australia and Canada – collectively, the J5 – agents have been sharing tips and data since 2018.

One of the biggest data dumps came shortly after FIOD seized and shuttered bestmixer.io.  That May 2019 operation yielded reams of user data in IP addresses and bitcoin addresses, which FIOD then shared at a crypto tax summit in Los Angeles late last year. 

“The J5 challenge in the United States at the end of 2019 was important in our fight against crypto criminality,” FIOD’s chief, Hans van der Vlist, said in a joint J5 statement. “The operational cooperation within the J5 is beginning to pay off.”

More bestmixer.io arrests may be around the corner; the J5 said further investigations “cannot be ruled out.”