Question: The San Quentin Six were six inmates at San Quentin State Prison in the U.S. state of California, they were accused of participating in an escape attempt, on which date, that left six people dead, including George Jackson, a co-founder of the Black Guerrilla Family?
Sentence (from "George Jackson (activist)"): The same year, he published "Soledad Brother: The Prison Letters of George Jackson", a combination of autobiography and manifesto addressed to a black American audience.
Relevant evidence: No