International Rivers points to the case of an Ethiopian journalist Reeyot Alemu who has been jailed for daring to criticize the government's centerpiece project.
Kastor was eighth at the 30km marker, sixth at the 35th and fourth at 40, easily passing the fading Ethiopian Elfenish Alemu with around a kilometer remaining in the 42.2-kilometer (26.2-mile) race to claim a surprise medal.