CINCINNATI — A University of Cincinnati officer who shot a motorist during a traffic stop over a missing front license plate was indicted Wednesday on a murder charge, with a prosecutor saying the officer “purposely killed him” and “should never have been a police officer.” Hamilton County Prosecutor Joe Deters announced the grand jury indictment at a news conference to discuss developments in the investigation into the July 19 shooting of Samuel DuBose, 43, by Officer Ray Tensing. Authorities have said Tensing saw a car driven by DuBose and missing the front license plate, which is required by Ohio law.