Controversy: Chinese swimmer Ye Shiwen

China’s Ye Shiwen competes in the women’s 200m freestyle heat at the London 2012 Olympic Games. (Hannibal / EPA)

July 30, 2012 8:04 PM PT

Top U.S. official describes Ye Shiwen’s feat in 400-meter individual medley as ‘impossible,’ as swimmer Caitlin Leverenz says it’s not ‘wrong’ for people to raise doping issues. Ye denies allegations.

Ye Shiwen, 16, swims in a 200m individual medley heat. (Leon Neal / AFP / Getty Images)

China’s Ye Shiwen backstrokes in a women’s 200m individual medley heat Monday. ( Leon Neal / AFP / Getty Images)

China’s Ye Shiwen leaves the pool after semifinals of the 200m individual medley in London. (Martin Bureau / AFP / Getty Images)