LITTLE ROCK, Ark. (AP) — A judge has overturned an Arkansas man's 1988 robbery and murder convictions and ordered prosecutors to either release or retry him.

District Court Judge Billy Roy Wilson granted a petition Tuesday by the Midwest Innocence Project, who appealed the convictions of John Brown. The group alleged the state withheld evidence that could have cast doubt on his guilt.

In 1992, Brown was convicted in the murder and robbery of an elderly woman in Fordyce, Arkansas. In 2015, one of Brown's co-defendants confessed to being alone at the murder.

The Midwest Innocence Project claimed that Brown's lawyer was "ineffective and corrupt."

The judge vacated Brown's convictions and gave the state 30 days to either release or retry Brown. A spokesperson for the attorney general's office says officials are reviewing the decision.