The top four finishers are obviously all on something. There's no doubt in my mind. Dibaba was waiving her arms around celebrating at the end while hardly breathing hard after closing in under 1:57. Give me a break. As the announcer said, "There has never been a final two laps close to that in a major women's 1500, even during the height of the documented Eastern European doping era."
I hope they can develop some improved testing in a hurry before the Olympics, but it is doubtful.