In July 2008, world class Russian track stars -- including world record holder Yelena Soboleva -- found themselves banned from the Beijing Olympics for a urine doping scandal. Some of the details emerged as recounted here (IOL, South Africa).
It appears that the IAAF suspected the Russians (inside informant?), and thus laid a trap -- a sting operation involving DNA. Obviously the IAAF compared DNA of prior urine samples with DNA of current urine samples; a discrepancy revealed the cheats.
The athletes were always ready for the International Association of Athletics Federations (IAAF) anti-doping officials and always provided clean urine samples.
"There were no 'no shows'," one official told Reuters. "The Russians were always there."
Suspecting that the results were too good to be true, the IAAF started storing Russian dope samples taken during competition throughout the 2007 season.
The upshot was a meticulous sting operation this year, after which seven Russian women were informed that the urine they had supplied was clearly not theirs because the DNA did not match that in the stored samples.
Five of them, including the world number one 800 and 1 500 metres runner Yelena Soboleva, had been bound for the Beijing Olympics.
A clear victory for the testers over the cheats, 20 years after the Ben Johnson doping scandal had revealed the extent of illicit doping in the central sport of the summer Olympics, was rightly trumpeted.