The hackers, both from Belarus, connected electronic devices to cash machines to get them to release thousands of euros.
Two suspects have been arrested after nearly a quarter of a million euros were stolen by hacking into cash machines across Europe.
Polish police arrested the two suspects, who are both from Belarus, in the Polish capital Warsaw on July 17.
They had allegedly been gaining access to ATM machines by drilling holes or melting parts of the machines to physically connect wires to a laptop. Then they were able to remotely tell the cash machine to dispense money.
Dozens of ATMs across Europe were targeted, with an estimated €230,000 stolen in total, according to Europol, which helped with the investigation.
The thefts occurred in at least seven European countries, and the criminals always targeted the same brand and model of ATM.
Police forces from six countries took part in the investigation, including Poland, Germany, Austria, Switzerland, the Czech Republic and Slovakia.