Spain's Javier Pascual Llorente has been named as the rider who failed a drugs test at the Tour de France.
Llorente was told on Monday that his B sample had confirmed a positive test for the banned substance EPO.
The Kelme rider faces a ban of up to two years but insists he is innocent of any wrongdoing and says he believes the way the test was conducted is to blame.
"I am completely calm about it but I don't have any confidence in what the French are doing," he said.
"Clearly there's persecution going on against Spanish cycling.
"I talked with doctor Walter Viru and he told me we'd never used the product in question, that everything was within the rules."
There was only one case of doping during the centenary Tour, according to the International Cycling Union (UCI).
Llorente returned the positive sample after the 12th stage, a 47km time-trial which was won by Tour runner-up Jan Ullrich.
The 32-year-old has had an exceptional season, beating Lance Armstrong to take the Tour of Murcia during the final time-trial stage and also winning the Ruta Del Sol through the Andalucian region of southern Spain.
The Spanish Royal Cycling Federation (RFEC) will now take up Llorente's case and could ban him for between one and two years if it finds him guilty.
Llorente, however, insists his positive result was down to "French detection methods, which are not reliable.
"It's a big coincidence that it's always the Spaniards who are caught - there's something fishy going on," he said.
"It was the same with Fran Perez and Aitor Kintana, who were unjustly punished," said Llorente, noting his countrymen had tested positive after the Tour of Romandy and Tour of Catalonia earlier this season.
Since the detection of EPO in urine samples was pioneered by a French laboratory, only one rider has been banned from the Tour and sanctioned - Spaniard Txema Del Olmo, who tested positive in 2001.
But because of recent scandals, there is still suspicion that some riders are continuing to use the substance, which helps to increase the number of red blood cells.
Lithuanian cyclist Raimondas Rumsas and Spaniard Francisco Perez have both tested positive for EPO this season.