The "B" sample of UFC light heavyweight champion Jon Jones' failed drug test from July 28 in Anaheim, California, has confirmed the presence of a banned substance, a United States Anti-Doping Agency spokesperson said Tuesday.

"Mr. Jones' 'B' sample has confirmed the 'A' sample findings," the spokesperson said. "Importantly -- as previously stated -- due process should occur before drawing any conclusions about this matter."

Last month, USADA informed Jones that he had tested positive for Turinabol, an anabolic steroid, on July 28. One day later, Jones (23-1) reclaimed his UFC title by knocking out Daniel Cormier at UFC 214.

Jones has denied knowingly taking a banned substance, and his team is investigating how the steroid entered his system. Jones' investigation into the possibility of tainted supplements is critical to his defense.

Jon Jones has denied knowingly taking a banned substance. He was informed last month that he tested positive for Turinabol on July 28. Christian Petersen/Zuffa LLC/Getty Images

It is normal for an athlete to request the results of a "B" sample under these circumstances. It is rare, however, that a "B" sample negates a positive test.

The result of Jones' win over Cormier is likely to be changed to a no-contest, although the California State Athletic Commission has not yet made that change. UFC did not immediately strip Jones of his title and has not commented on the status of the division.

This is the second failed drug test of Jones' career. UFC was forced to pull him from a championship bout in July 2016 after he tested positive for multiple anti-estrogenic agents. Jones later told USADA that the substances came from a contaminated sexual enhancement pill. He was suspended one year for negligence.

Per UFC's anti-doping program, Jones faces a maximum suspension of four years for a second offense. Technically, he potentially faces sanctions from two different bodies: CSAC and USADA. However, it's possible USADA will simply mirror CSAC's ruling.

Jones reserves the right to appeal under both agencies.

According to CSAC, Jones passed multiple out-of-competition tests leading up to his victory at UFC 214. The failed urine test was administered by USADA on July 28, one day before the bout. Jones then passed a blood test on July 29. That does not significantly aid Jones' case, however, as blood tests do not test for Turinabol.

Going into his rivalry bout with Cormier in July, Jones adamantly denied using performance-enhancing drugs. He referred to Cormier's suggestions to the contrary as "one of the most insulting things you can do to a guy who's accomplished the things I've accomplished."

Widely considered the greatest fighter of all time, Jones has endured a tumultuous three-year span. UFC stripped him of his title in 2015, after he was arrested on hit-and-run charges in Albuquerque, New Mexico. He remains the only champion ever stripped of a title for disciplinary reasons.

Last weekend, Jones wrote a short post on social media via Twitter: "You gotta live with tomorrow despite how you're feeling today."