A Missouri man spared prison for 13 years by mistake is obviously "rehabilitated" and imprisoning him would be a waste of money, a judge said Monday. The state Department of Corrections only noticed last year that Cornealious "Mike" Anderson had never been ordered to report to prison to serve a 13-year stretch for armed robbery. Anderson, now 37, was sentenced in 2000 for holding up a Burger King manager at a bank's night drop. Mississippi County Associate Circuit Judge T. Lynn Brown agreed with Anderson's lawyer that he should get credit for the time he spent waiting to be ordered to prison -- and building up a construction business, paying his taxes and becoming a married man with four children. "I believe that continuing to incarcerate you serves no purpose," Brown said. "It would be a waste of taxpayer dollars. You obviously are a rehabilitated man." Anderson had a lot of support with thousands of signatures on an online petition started by Change.org. His victim also supported freeing Anderson. U.S. marshals arrested him last year at his home and took him to prison.