Question: The Brink's robbery of 1981 was an armed robbery and three related murders committed on October 20, 1981, which were carried out by six Black Liberation Army members, including Mutulu Shakur, he was a close friend of who?
Sentence (from "Mutulu Shakur"): Mutulu Shakur (born Jeral Wayne Williams; August 8, 1950) is an American black Revolutionary.
Relevant evidence: No