Two other suspects in the killing, Tad Carroll, 41, and Barbara Hamel, 47, are already in custody.
They're accused of following Bui from Hawaiian Gardens to Santa Ana, taking his $10,000 winnings and then running him over as they fled the scene.
Carroll and Hamel will be arraigned Oct. 17.
Ross, of Long Beach, allegedly saw the victim cash in his winnings and called Carroll and Hamel to set up the robbery.
