Officers from Poland’s Central Bureau for Combating Cybercrime (CBZC) arrested four suspected members of an organized cybercrime group accused of SIM swap attacks, cryptocurrency theft, and money laundering.

The operation involved agents from the U.S. Federal Bureau of Investigation (FBI) and Homeland Security Investigations (HSI). The investigation is being supervised by the Regional Prosecutor’s Office in Kraków and remains ongoing.

“The investigation revealed that members of the group, operating within organized structures, deliberately breached IT systems. Using specialized software and social engineering, the perpetrators gained unauthorized access to the infrastructure of entities cooperating with telecommunications operators and employee email accounts,” the CBZC said in an announcement.

Investigators said the stolen information enabled the group to carry out SIM swap attacks by taking control of victims’ phone numbers. Access to SMS messages and email accounts allowed the suspects to take over cryptocurrency exchange accounts and transfer digital assets under their control.

“The perpetrators, turning this into a regular source of income, used numerous personal bank accounts in Poland and abroad, international payment platforms, and multi-currency digital wallets for transfers. The total value of the funds legalized in this manner is estimated to exceed tens of millions of zlotys,” CBZC added.

Prosecutors charged the suspects with participating in an organized criminal group, breaking into computer systems, and money laundering. If convicted, they could face prison sentences of up to 25 years. A court ordered all four suspects into pretrial detention.

CBZC noted that the international nature of the investigation limits the amount of information authorities can disclose at this stage.