The Associated Press is reporting that longtime Marvel and DC comic writer Dwayne McDuffie has passed away of unknown causes. There are no indications yet as to what caused his death or even where he died. McDuffie was just in Los Angeles to promote his animated film All-Star Superman, which was released in stores today and stars Christina Hendricks as the voice of Lois Lane. McDuffie is interviewed above at the event by the Superman fansite Superman Homepage.