TheBlock
Polish authorities arrested four members of a criminal group accused of running SIM-swap attacks against cryptocurrency holders, stealing digital assets, and laundering the proceeds. The operation was supported by FBI and Homeland Security Investigations agents operating on Polish soil.
Why it matters
Onchain investigator ZachXBT has alleged that one of those detained is Wojtek Kulisz, the threat actor known online as "Merry". The identification rests on designer items visible in footage of the seized assets, items Kulisz had previously posted to his public Instagram. SIM-swap fraud has been one of the persistent drains on retail crypto balances, and the case links a named online persona to a coordinated cross-border arrest.
Market impact
The arrest does not move token prices, but it tightens the runway for social engineering crews operating in Europe. Cross-border cooperation with US federal agencies on a fraud case that targets crypto users directly raises the cost of the same playbook for any group still running it. Expect other investigators and exchanges to revisit cold cases where the same TTP and asset patterns appear.
Frequently asked questions
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Who was arrested in the Polish SIM-swap case?
Polish authorities arrested four members of a criminal group accused of SIM-swap attacks on crypto holders, digital asset theft, and money laundering, with FBI and HSI agents supporting the operation.
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Who is 'Merry' and how was he identified?
Onchain investigator ZachXBT alleged that one of those detained is Wojtek Kulisz, known online as 'Merry'. The identification rests on designer items visible in seized-asset footage that Kulisz had previously posted to his public Instagram.
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What is a SIM-swap attack in crypto?
A SIM-swap attack is a social engineering fraud in which attackers convince a mobile carrier to transfer a victim's phone number to a SIM they control, then use SMS-based 2FA to drain exchange and wallet accounts.
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Did US agencies participate in the Polish arrests?
Yes. FBI and Homeland Security Investigations agents supported the Polish operation, signaling that US federal agencies are treating crypto-targeted social engineering fraud as a cross-border enforcement priority.
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What is the market impact of the arrests?
The arrests do not move token prices. The structural read is that the cost of running SIM-swap fraud in Europe has risen, and other investigators and exchanges are likely to revisit cold cases matching the same tactics.
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