Police are looking for four people in connection with the beating of California Quarter Horse trainer Robert Gilbert seen leaving the same casino where Gilbert had just won several thousand dollars.Cypress police on Friday released a security videotape from the Pachanga Indian Casino in Temecula, Calif., where two men and two women were leaving moments before Gilbert had just won the money. The four people aren't considered suspects at this point, police said, and are wanted for questioning.Lt. Mike Idom said Gilbert had dropped off a horse in the area and was at the casino for about 13 hours before leaving about 3 a.m. Wednesday.He was found a couple hours later badly beaten in a remote part of the parking lot of the Los Alamitos race track. Police said Gilbert had been robbed of his winnings.Gilbert, 56, remains in critical condition and on life support at a Los Angeles-area hospital. His brother, Tom, said at a press conference Friday that Rob has a 20 percent survival rate and is in a comatose state.Los Alamitos track officials said they are offering a $100,000 reward leading to the arrest and conviction of the person or persons responsible for the attack.