The FBI has launched an investigation of the Corrections Corporation of America over the company's running of an Idaho prison with a reputation so violent that inmates dubbed it Gladiator School." CCA has operated Idaho's largest prison for more than a decade, but last year, CCA officials acknowledged it had understaffed the Idaho Correctional Center by thousands of hours in violation of the state contract. CCA also said employees falsified reports to cover up the vacancies. The announcement came after an Associated Press investigation showed CCA sometimes listed guards as working 48 hours straight to meet minimum staffing requirements. The understaffing has been the subject of federal lawsuits and a contempt of court action against CCA. The ACLU sued on behalf of inmates at the Idaho Correctional Center in 2010, saying the facility was so violent that inmates called it "Gladiator School" and that understaffing contributed to the high levels of violence there. In 2012, a Boise law firm sued on behalf of inmates contending that CCA had ceded control to prison gangs so that they could understaff the prison and save money on employee wages, and that the understaffing led to an attack by one prison gang on another group of inmates that left some of them badly injured.