The driver picked up the passenger at 1:10 a.m. at the San Leandro BART station. He took him to the 600 block of Marina Boulevard and the passenger walked toward a car parked nearby, police said.
But as the passenger got out, another man wearing a ski mask opened the front door of the cab, punched the driver in the face and demanded money, police said. The driver handed over his money and the attacker fled.
Police believe that the suspect and the passenger were working together to rob the driver. The passenger was described as a thin black man in his 20s, about 6 feet 2 inches tall. He had long braided hair and was last seen on Alvarado Street.
Anyone who witnessed the attack has been asked to call San Leandro police at (510) 577-2740.