Ricardo Ricco, who upset some big names in biking during this year’s tour, was caught doping after the drugmaker planted a traceable molecule in the banned stamina-building drug he had taken, according to the World Anti-Doping Agency. And so the 24-year-old was kicked off after testing positive for EPO, or erythropoietin.

Roche included a molecule in the third generation of EPO, called Continuous Erythropoiesis Receptor Activator (CARA), that acted as a flag in drug tests showing when an athlete was using the substance, John Fahey, WADA’s chief, tells the Australian Broadcasting Corporation.

Until this year’s Tour, the CARA EPO, which is released into the body more slowly than its predecessors, had been thought to be virtually undetectable by drug testers, ABC reports. But Fahey says cooperation with drugmakers is the way to fight drug cheats.

“There’s more and more of this occurring,” Fahey tells ABC. “The more cooperation the scientists can have with the drug companies in the detection of performance-enhancing drugs the greater the likelihood is they will be detected when tests are undertaken.”

Ricco is one of three riders to test positive for EPO at this year’s tour, tarring the race once again with a drugs controversy. He denied using the substance, which was developed to boost oxygen levels in the blood of people with anemia who also have kidney disease. It has been banned in sports as it gives athletes an unfair advantage over their rivals.