“I sang because they promised I would not be prosecuted,” Davis wrote in his memoir.

On the night of the shooting, Shakur had been traveling in the passenger seat of a BMW driven by Marion Knight, the rap mogul known as Suge, toward a postfight after-party at Club 662, a new venue backed by their record label, Death Row.

Davis, a self-described member of the Crips, wrote in his memoir that he, Anderson and others had armed themselves and waited in the nightclub parking lot, hoping to confront Shakur and Knight, who were associated with the Bloods, about the earlier violence.

When the rapper failed to materialize, Davis said, the group waiting for him left for its hotel, only to encounter Shakur and Knight talking to fans at a red light. “As they sat in traffic, we slowly rolled past the long line of luxury cars they had in their caravan, looking into each one until we pulled up to the front vehicle and found who we were seeking,” Davis wrote.

Davis said Shakur’s crew had committed “the ultimate disrespect when they kicked and beat down my nephew” — an attack thought to be retribution for an earlier robbery of one of Shakur’s friends. In his memoir, Davis described the “strict code” of the streets that its participants “live, kill and die by.”

“Tupac’s and Biggie’s deaths were direct results of that code violation and the explosive consequences when the powerful worlds of the streets, entertainment and crooked-ass law enforcement collide,” he wrote.

Davis added that he had been considered a “prime suspect” in both murders, and called writing about the events for his book “therapeutic.”