Relatives of a 75-year old southern Illinois cab driver who was shot and killed more than three years ago said they are waiting for the cases in the killing to be resolved. One of the defendants, 18-year old Christopher Wells of Mount Vernon, has pleaded guilty to a first-degree murder count related to the May 2011 killing of Charles Ellis of Mount Vernon.  Wells is awaiting sentencing.  Three other defendants have pleaded not guilty and await trial.  Ellis was found dead in his cab after being shot in the back during what police suspect was an attempted robbery, authorities said.  The family’s wait for disposition of the court cases is “just hard to believe,” one of the victim’s sons, Bobby Ellis, told WSIL-TV.