SPRINGFIELD, Ill. (AP) — Illinois prison officials have identified a former Tamms super maximum-security prison inmate as responsible for a knife attack Monday that injured three guards. Department of Corrections spokeswoman Nicole Wilson confirmed the inmate was moved to Pontiac Correctional Center from Tamms when it was closed in 2012. The inmate is serving time for murder and aggravated battery. The Associated Press is not naming him because he has not been charged with the stabbing. Opponents of closing Tamms warned the supermax prison was the best way to keep inmates and guards safe. Wilson says Pontiac staff received a tip that the inmate had a homemade weapon in his cell. When three officers entered the cell, he stabbed them with a metal shank. The officers were treated for non-life-threatening injuries at a hospital.