Tomashova won gold at the 2003 and 2005 world championships
Seven Russian athletes provisionally suspended for doping offences were tipped off ahead of visits from the testers, BBC Sport understands.
The International Association of Athletics Federations grew suspicious because the athletes were always available when the testers arrived.
Athletes are not normally immediately available for out-of-competition tests based on the whereabouts system.
"But the Russians were always waiting," said BBC Sport's Gordon Farquhar.
Five of the seven - Yelena Soboleva, Tatyana Tomashova, Yulia Fomenko, Darya Pishchalnikova and Gulfiya Khanafeyeva - were bound for the Beijing Olympics but they will now not compete at the Games.
The other two athletes are Svetlana Cherkasova and Olga Yegorova.
And Farquahar added: "IAAF sources say they began investigating the seven suspended athletes when testers expressed surprise at their unfailing punctuality.
"The athletes have an hour to show up at the specified location and give a sample, but the Russian athletes were always ready.
"The IAAF sources also say the Russian Federation knew of the problem more than two weeks ago, and they're confident the suspected tip-offs haven't come from within their own organisation."
The athletes were targeted for more than a year after the testers became suspicious.
Russian Yegorova was booed on her way to claiming the 5,000m title at the World Championships in Edmonton in 2001.
These rule violations were established following the deliberate storage of samples by the IAAF and re-analysis using comparative DNA techniques
She had tested positive for EPO but had been reinstated in the event on a technicality concerning the drugs test.
Before the heats for the women's 5,000m Paula Radcliffe and Great Britain team-mate Hayley Tullett held up a sign in the stands reading "EPO cheats out."
Soboleva - the reigning 1500m world indoor champion - is the world leader over 800m and 1500m this year, while Tomashova was world champion in 2003 and 2005 and claimed silver at the Athens Olympics four years ago.
Fomenko finished second behind Soboleva over 1500m at the world indoor championships in Valencia earlier this year.
The two field-eventers are also of pedigree, with Pishchalnikova the reigning European discus champion and hammer thrower Khanafeyeva a former world record holder.
The seven have been charged under IAAF rules for a "fraudulent substitution of urine which is both a prohibited method and also a form of tampering with the doping control process", according to a statement from the world governing body.
The statement continued: "These rule violations were established following the deliberate storage of samples by the IAAF and re-analysis using comparative DNA techniques."
The IAAF added the suspensions were "the result of a specific investigation which was instigated and carried out by the IAAF for more than a year".
And the statement concluded: "The IAAF will make no further comment until a final decision has been taken by the ARAF (All Russia Athletics Federation), which now takes over the responsibility to adjudicate these cases."
The athletes have up to 14 days to request a hearing with the national member federation.
If a hearing is requested, it must be held within a period of two months but the ARAF has said that they will not take place until after the Olympics.
The Beijing Olympics athletics schedule is set to get under way on Friday, 15 August.