Hyungwon Kang / Reuters
U.S. Department of Homeland Security analysts work at the National Cybersecurity & Communications Integration Center (NCCIC) located just outside Washington in Arlington, Virginia
The group is well known to U.S. authorities, and it has stolen more than 160 million credit-card numbers over the past seven years.
Unnamed officials told Bloomberg that aside from Neiman Marcus, the group has also stolen information from over 100 other companies, including as Citigroup Inc. and J.C. Penney Co.
The FBI and the U.S. State Department have been attempting to persuade Russian officials to arrest members of the syndicate with little success, according to two former U.S. officials. In 2008 and 2009, a series of trips to Russia by senior FBI agents seemed to signal enhanced Russian cooperation.
Russia, despite extensive information from the FBI and pledges of cooperation, carried out no arrests. It is now thought that Russia was using the FBI's information to discover talented hackers for recruitment.
The Russian government allegedly maintain a network of affiliated hackers that it can use for targeted cyber attacks against foreign nations. The hackers are not hired officially by the government in order to maintain plausible deniability.
Russia has used hackers before to cripple the Estonian financial sector. Currently, Russia is engaging in a low-grade, but quickly escalating, cyber war in Ukraine.