After a thorough investigation into the circumstances of Rivera’s case, USADA concluded that the clenbuterol levels detected in his sample were inconsistent with what could be expected from meat contamination. Furthermore, Rivera was unable to provide independently verifiable evidence to support his claim that he had traveled to Northern Mexico and ingested meat in the days leading up to the relevant sample collection. Thereafter, Rivera opted to have his case submitted to a neutral arbitrator for resolution.
In advance of the arbitration hearing, USADA’s ongoing investigation revealed that several pieces of evidence presented by Rivera to USADA and the arbitrator had been falsified to support the athlete’s claims that the substance had originated from contaminated meat in Mexico.
Under the UFC Anti-Doping Policy, deceitful or obstructive conduct intended to avoid the detection or adjudication of an anti-doping policy violation may be regarded as aggravating circumstances, which can lead to an increased period of ineligibility. In this case, the independent arbitrator concluded that Rivera’s conduct warranted an increase from the standard two-year period of ineligibility for a first offense, to the maximum four-year period of ineligibility due to aggravating circumstances.
https://ufc.usada.org/francisco-rivera-recieves-doping-sanction/