The hardware firm has retained Data Forte, a team led by a former U.S. Naval Criminal Investigative Service officer to work with FBI agents on the illegal activity, according to Reuters.
Security detectives from Guidance Software and Protiviti consultants are also involved in the investigation, after Sony discovered personal details, credit and debit card information and online passwords and identities were stolen.
As a result, the popular PlayStation Network service has been offline for two weeks, with developers and content providers unable to sell services and games to consumers.
Sony has promised to make amends for the downtime but has so far been unable offer any concrete timings for reinstating the service.