Ukrainian authorities have arrested five people accused of being "key subjects" in an international criminal ring that used the Zeus Trojan to steal $70 million from online bank accounts.
The arrests are part of an international operation, dubbed Trident Breach, that has seen over 70 people charged in the US and 11 in the UK over the past few days.
According to the FBI, Operation Trident Breach began in May 2009, when agents in Omaha, Nebraska, were alerted to ACH batch payments to 46 separate bank accounts throughout the United States.
The Bureau began working with State, federal and foreign agencies in the Netherlands, Ukraine, and the UK to crack the ring, which is alleged to have targeted small to medium-sized companies, municipalities, churches, and individuals, infecting their computers using a version of the Zeus Botnet.
The malware, which captured passwords, account numbers, and other data used to log into online banking accounts, was used to try and steal $220 million, with actual losses of $70 million, says the FBI.
The US arrests relate to the money mule organisation that set up fake bank accounts to transfer the stolen funds, but the five detained by Ukraine's SBU "were key subjects responsible for this overarching scheme".
FBI Director, Robert Mueller, says: "No one country, no one company, and no one agency can stop cybercrime. The only way to do that is by standing together. For ultimately, we all face the same threat. Together, the FBI and its international partners can and will find better ways to safeguard our systems, minimise these attacks, and stop those who would do us harm."