Tupac ShakurA convicted murderer, long suspected of involvement in the 1994 Quad Studios shooting of Tupac Shakur, has finally admitted to committing the crime, and has accused Game's manager, Jimmy "Henchmen" Rosemond -- founder of Czar Entertainment -- of masterminding the botched robbery, which left the legendary rapper shot five times.

"I want to apologize to his [Tupac's] family and for the mistake I did for that sucker [Rosemond]," Dexter Isaac told AllHipHop.com yesterday (June 15), on the eve of Tupac's 40th birthday.

In an explosive confession dedicated to his former friend, whom he helped to launch entertainment company Henchmen Entertainment in 1989, Isaac explained that he has "stayed silent in prison for the past 13 years, doing a life sentence like a real soldier should," but that he is "tired of listening to your [Rosemond's] lies."