St. Louis prosecutors have dropped purse-snatching charges against a man who had avoided prison for 13 years because of a clerical error after he was convicted of robbing a restaurant.

Cornealious Anderson, 37, had been sentenced in 2000 for an armed robbery in St. Charles County but was never told when or where to report. He went about his life, starting his own business, coaching youth football in Webster Groves, Missouri, a St. Louis suburb.

His case drew national attention after prison officials found the mistake in July 2013. Anderson was imprisoned for 10 months before a judge set him free in May, declaring him "a good man and a changed man."

But in November, Anderson was arrested after a woman's purse was snatched at a White Castle restaurant in St. Louis. St. Louis Circuit Attorney Jennifer Joyce said Thursday that an investigation by her office cast doubt on the case, prompting her to drop charges of second-degree robbery.

"Prosecutors gathered surveillance video from area businesses and the media, interviewed additional witnesses and worked with the defense attorney to ensure all available information was reviewed," Joyce said in a statement. "The investigation revealed questions regarding the procedures by which the victim and witness identified the suspect."

Patrick Megaro, Anderson's attorney, did not immediately return messages left Friday.

Joyce apologized to Anderson and said her office is working with police "to review internal policies and procedures in this case."

Messages seeking comment from police were not returned, but Maj. Michael Caruso told the St. Louis Post-Dispatch that he would not go as far as to issue an apology to Anderson.

"The system worked the way it was designed to work and at the end he was released without going to trial," Caruso said. "In this case their investigation uncovered some things that ours didn't -- and that's part of the system -- and based on that information, the charges were dropped."

In the 2000 case, Anderson robbed a Burger King worker at gunpoint. He waited for information on when and where to report to prison, even asked his attorney, but the order never came, he told The Associated Press last year.

So he started a carpentry business, got married, raised kids and volunteered at his church.

When his prison term was scheduled to end in July 2013, corrections officials realized that Anderson and never served his time. He was home preparing breakfast for his daughter one morning when eight U.S. marshals arrived and took him to prison, where he remained until a May hearing before Mississippi County Judge Terry Lynn Brown.

"You've been a good father," Brown said as he set Anderson free. "You've been a good husband. You've been a good taxpaying citizen of the state of Missouri. That leads me to believe that you are a good man and a changed man."

The purse-snatching allegation seemed to call that into question, though Megaro said from the outset that Anderson was wrongly accused.

Anderson was arrested near the site of the robbery about a half-hour after the robbery. Anderson told police he had been at a family birthday party at a bar about a mile from the White Castle, and was walking to his car.

Police took Anderson to the scene of the crime, where the victim and another witness identified him as the robber. Megaro said Anderson had an alibi and 40 people who could back him up.