GULFPORT, Miss. (AP) - A man robbed a Mississippi Subway sandwich shop with a BB gun in the hopes it would get him sentenced to life in prison.

Forty-five-year-old Robert S. Johnson pleaded guilty Tuesday to armed robbery.

The Sun Herald of Biloxi reports Johnson used the cash from the September robbery to buy crack and tried to overdose. When that didn't work, he turned himself in.

Johnson had promised himself when he was released from prison months earlier that he'd return if he went back to crack. Johnson's attorney, Angela Blackwell, told Judge Lisa Dodson that Johnson has bipolar disorder. He's now on an antidepressant.

Prosecutor Matthew Burrell said Johnson asked for a life sentence. Instead, Dodson sentenced Johnson to 15 years in prison and ordered him to get a GED while there.