Salwa Eid Naser was already being investigated for missing doping tests when she raced to an upset win in the 400 meters at the world track and field championships. The Athletics Integrity Unit confirmed Sunday that Naser was already under scrutiny for three whereabouts failures prior to her world championship win in Doha in October. That means that Naser could be stripped of her gold medal if she's found guilty. The Nigeria-born sprinter, who represents Bahrain, surged past Olympic champion Shaunae Miller-Uibo to win in 48.14 seconds, the fastest time since 1985. Three violations within 12 months can lead to a suspension if the athletes cant justify why they werent available for testing.