MOSCOW (AP) — World champion boxer Alexander Besputin is facing a doping charge after a drug test showed an abnormal result.

Besputin won the WBA welterweight title in November by unanimous decision against fellow Russian Radzhab Butaev, a result that could be affected by the drug test.

The Russian Boxing Federation said it has requested documentation on the test because it has started its own investigation.

Besputin told Russian news agency RIA Novosti he is “clean” and “this substance could get in through food or supplements.”

Besputin is based in California and is unbeaten with a 14–0 record. The win over Butaev in Monaco was his first pro fight outside the United States.

The WBA last month ordered Besputin to defend his title against Cuban Yordenis Ugas before March 29, but no date has been set.