ST. LOUIS (AP) — A man who was on the verge of walking out of prison this week after a judge found evidence of “actual innocence" and overturned his murder conviction now faces a fresh legal hurdle. The person blocking Christopher Dunn's freedom is Missouri Attorney General Andrew Bailey, who is fresh off an unsuccessful battle to keep another woman whose murder conviction was reversed imprisoned.

Political scientists say Bailey's efforts are a way to appear tough on crime and shore up votes in advance of a tough primary race. Judges and defense attorneys are voicing frustration. "His actions are causing undue harm to this innocent individual and is a stain on our legal system,” Michael Heiskell, president of the National Association of Criminal Defense Lawyers, said when asked about Bailey's opposition to Dunn's release.

Here are some things to know: Dunn, who is Black, was 18 in 1990 when 15-year-old Ricco Rogers was killed. Among the key evidence used to convict him of first-degree murder was testimony from two boys who were at the scene of the shooting. Both later recanted their testimony, saying they had been coerced by police and prosecutors.

Judge Jason Sengheiser on Monday overturned the murder conviction of the now 52-year-old and ordered his immediate release. Bailey’s office appealed, and prison officials declined to release Dunn. Sengheiser then held an emergency hearing Wednesday and threatened to hold the warden in contempt if he didn't free Dunn within .