SOCHI (AFP) - Russia goes into the Winter Olympic Games facing renewed scrutiny of its record on doping, despite years of efforts aimed at shedding its reputation as one of the worst drug offenders in sport.
The nightmare of many Russian sports officials came true in the days leading up to the Olympics when one of the potential female Russian stars of the Sochi Games, biathlete Irina Starykh, withdrew after an 'A' sample tested positive.
She is now waiting the 'B' sample result.
Meanwhile, Germany's WDR television broadcast an investigative report alleging its reporters had been offered a new muscle growth substance called "Full Size MGF" by Russian researchers in Moscow.
Russia has in the last years for the first time in its history moved to make genuine progress in the fight against doping, finally creating its own anti-doping agency Rusada in 2008.
The breaking point appears to have been a scandal that broke ahead of the 2010 Vancouver Olympics when three of Russia's best-known biathletes - Dmitry Yaroshenko, Albina Akhatova and Yekaterina Yuryeva - were disqualified for doping with blood booster EPO.
The scandal cast a shadow over Russia's participation in Vancouver and warnings from the very highest level in the IOC that Russia had to get serious.
"I tend to be a glass half-full rather than a glass half-empty man. I think the Russians have learnt the message," was the cautious assessment of Craig Reedie, the president of the World Anti-Doping Agency (Wada), in Sochi.
Rusada is now carrying out regular testing of athletes, in work that is generally praised by international experts and has already uncovered scores of cheats.
But suspicions are taking longer to change and Russia seems far from being able to boast that its sport is clean.
Last month, London Olympics bronze swimming medallist and the pin-up of the sport in Russia, Yulia Efimova, was handed a provisional suspension after she tested positive for a banned steroid.
The positive test by Starykh, 26, sent shockwaves through biathlon and all Russian sport, although officials emphasise that the 'B' sample should be awaited before drawing conclusions.
She was seen as an up-and-coming golden girl of the ski-and-shoot discipline, Russia's second most-watched winter sport after ice hockey.
"I have fallen into a difficult situation and I feel obliged to announce my decision to leave the team for an indefinite period of time," she said in comments released by the Russian Biathlon Union.
"This news was hugely unexpected for me. Believe me, I really regret that this story has become linked to my name," she added.
What substance Starykh tested positive for has not been made public.
A second Russian biathlete also tested positive and has not been named officially. She is believed to be a well-known athlete who had previously served a doping ban but was not in the Olympic squad.
The news was a massive setback for biathlon in Russia, which is headed by the billionaire tycoon and Brooklyn Nets basketball team owner Mikhail Prokhorov.
One of Russia's senior biathlon coaches, the experienced German trainer Wolfgang Pichler, told Russian media that Starykh's exit on the eve of the Olympics would not hurt the results but the image of Russia.
"Whenever there is a good result someone is going to point the finger. This is very sad," he said.
Meanwhile there are also questions over the Mechano Growth Factor offered to the WDR team in Moscow. They were offered 100mg of the substance for US$100,000 (S$127,000) by a researcher linked to the Russian Academy of Sciences. So far it has only been tested on animals.