As members of two California gangs poured out of a Las Vegas boxing match in September 1996, Tupac Shakur, the most famous rapper in the country at the time, sucker punched a rival.

The man hit the ground, and the mob attacked. Shakur, along with Death Row Records executive Marion "Suge" Knight and members of the Bloods street gang, beat the victim until security showed up. The man declined medical treatment and wouldn’t tell the police what happened.

But he did tell his uncle, Duane Keith “Keffe D” Davis.

Davis, a leader of the Crips street gang, wanted to help his nephew get revenge. But in a Drug Enforcement Administration report detailing a secret police interview, obtained by USA TODAY and filed in court earlier this year, Davis said he had another reason to go after Shakur and Knight: Sean “Diddy” Combs had placed a $1 million bounty on the two men’s heads.

Hours after the beat-down at the hotel, Shakur was shot in a drive-by. He died several days later. Knight was grazed in the head and survived.