Ignoring evidence of faulty convictions:
As four men sat in prison for a murder they didn't commit, records show that state investigators sent proof of their innocence to a North Carolina prosecutor, but he never revealed it to the convicted men.
He didn't have to. Nothing in North Carolina's legal standards requires a prosecutor to turn over evidence of innocence after a conviction.
In this particular case, the District Attorney was provided solid evidence that five men he'd sent to prison were innocent, but he chose to ignore that evidence and let them remain incarcerated. Not only should there be a Bar Association rule in place to discourage that, there should also be a criminal charge for an officer of the court who does that. He might as well have kidnapped these people and chained them in his basement.