Mega bank Credit Suisse has filed a lawsuit in San Francisco in an attempt to unmask the mystery person who sent an email to the police and press in multiple countries with the personal details of ex-employees, Bloomberg reports. The emailer, who assumed the name of CEO Thomas Gottstein and personal details like social security numbers and bank accounts, was apparently trying to expose a data breach and demanded recipients to “take action against the bank.” The sender claimed to have details for hundreds of thousands more employees. Bank officials believe it may be an inside job, and have claimed in their suit that the creepy campaign is an “apparent effort to inflict the maximum damage possible to Credit Suisse.”