The group started the investigation after they learned their visitors were victims of credit card data theft. While the group say the investigation is ongoing, they confirmed the security breach.
The security breach is said to be occurred between October 2013 to early November 2013.
The group apologized for the security breach. They also urged customers to monitor their credit card statements carefully for fraudulent charges.
"We have been working closely with law enforcement officials and are providing them with all available information to support their effort to identify the criminals who undertook this act." the group said in its statement.