Anthony Sims has been incarcerated in a New York state prison for over 23 years for a murder in Brooklyn he very likely didn't commit. The evidence strongly points to another man, Julius Graves, as the killer. The prosecutor who tried and convicted Sims – and who later became head of the District Attorney's wrongful conviction unit – must have known that proof of Sims' guilt was weak and that more potent proof pointed to Graves as the killer. But once the police quickly arrested Sims, the case lurched forward and it became easier to prosecute Sims and use Graves and his friends as witnesses. It is hard to believe that the prosecutor who brought Sims to trial was not skeptical of Sims' guilt. And this raises the unsettling question: Do prosecutors who bring defendants to trial struggle with whether they may be prosecuting an innocent person?