A Chicago man with a long criminal history was sentenced to 15 years in federal prison after he was convicted of firing a gun into the open grave of a man murdered just two days prior, authorities said. U.S. District Judge John J. Tharp Jr. handed down the sentence Wednesday after Elston Stevenson, 57, pleaded guilty to one count of illegal possession of a firearm by a felon, according to a news release Monday from the U.S. attorney’s office in Chicago.