In 1966, William J. Barnes shot a Philadelphia police officer. A despicable act. He deserved to go to jail and he did. The shooting left the officer crippled until his death in 2007. The district attorney decided that the officer’s death in 2007 was the result of the shooting in 1966 and charged Barnes with murder even though he had fully served his sentence for the shooting.

Barnes was on parole and working as a janitor when he was arrested for murder. At the murder trial in 2010, a Philadelphia jury was not convinced that the 1966 shooting led directly to the officer’s death in 2007. Barnes was acquitted. Case closed, right? Hardly. As of Friday, the 75-year-old Barnes remained in jail even though he was acquitted. Why?