OKLAHOMA CITY (AP) — The U.S. Supreme Court has declined to hear an appeal from an Oklahoma man who was sentenced to death for the 1992 murder of a convenience store owner during a robbery.

Emmanuel Littlejohn had asked the court to consider whether his sentence was unconstitutional because jurors didn't hear of how brain damage could have explained his actions, The Oklahoman reported . The 46-year-old has admitted to taking part in the robbery, but he denies that he fired the shot that killed Kenneth Meers.

Littlejohn's attorney, Randy Bauman, wrote in a brief to the court that a lack of impu...