The filing follows another lawsuit this week from two other former Sony employees accusing the studio of being negligent by not bolstering its defenses against hackers before the attack. It claims emails and other leaked information show that Sony's information-technology department and its top lawyer believed its security system was vulnerable to attack, but that company did not act on those warnings. Sony potentially faces tens of millions of dollars in damages from a class-action lawsuit, said Jonathan Handel, an entertainment law professor at the University of Southern California Gould School of Law.