A 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 "Henchman" 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 today (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."

"In 1994, James Rosemond hired me to rob 2Pac Shakur at the Quad Studio," said Isaac, who is currently housed in Brooklyn, N.Y.'s Metropolitan Detention Center. "He gave me $2,500, plus all the jewelry I took, except for one ring, which he wanted for himself. It was the biggest of the two diamond rings that we took. He said he wanted to put the stone in a new setting for his girlfriend at the time, Cynthia Ried. I still have as proof the chain that we took that night in the robbery."

While Tupac survived the shooting, which took place on November 30, 1994, in Manhattan's Quad Recording Studios, and left him shot twice in the head, the incident directly instigated the deadly East Coast-West Cost rap feud, which resulted in the shooting deaths of both Tupac and his East Coast rival Biggie Smalls.

Isaac's shocking statement goes on to hint at future revelations regarding the fallen rappers, even drawing Bad Boy honcho-turned-entertainment mogul Diddy into the fray, claiming that Rosemond will "flip" on Biggie's former cohort for his involvement in the shootings.

"Now I'm not going to talk about my friend Biggie's death or 2Pac's death, but I would like to give their mothers some closure. It's about time that some one did, and I will do so at a different time," Isaac continued ominously. "Jimmy, you and Puffy like to come off all innocent-like, but as the saying goes: You can fool some of the people some of the time, but you cannot fool all of the people all of the time. Mr. Rosemond, I ask you: Are you going to flip on Puffy when the feds get you? To save yourself like you have done in the past?"

Rosemond, who manages rapper Game, singer Sean Kingston and Mike Tyson, among others, is currently still on the lam, facing federal cocaine conspiracy charges, and has been accused of being a government informant by the New York Daily News, 50 Cent and others.

Isaac is currently serving life in prison for the robbery and murder of a Brooklyn taxi-cab driver.