Police responding to a report of a car hitting a curb near the Las Vegas Strip say they found Knight standing over his longtime girlfriend with a knife in his hand.
Police say the woman tried to run from the car, but Knight grabbed her.
He's accused of having the drugs Ecstasy and hydrocodone when he was arrested.
Knight's lawyers, David Chesnoff and Richard Schonfeld, declined to comment.
Knight is co-founder of the hip-hop label Death Row Records.
