Jon Jones is trying to prove his innocence to the U.S. Anti-Doping Agency (USADA).

UFC sources learned that Jones took a polygraph test last month. The test was taken by “Bones” in an effort to prove he didn’t knowingly take performance enhancing drugs ahead of his UFC 214 title bout.

Neither the UFC or USADA asked Jones to take the test. “Bones” took the test on Dec. 7. It was conducted by the PGP Polygraph & Interviewing Service. This took place in Albuquerque, New Mexico.

Back in July 2017, Jones challenged Daniel Cormier for the UFC light heavyweight title. Jones initially emerged victorious, capturing the 205-pound gold via third-round knockout. All seemed right as the newly crowned champion was gracious to Cormier and talked about the type of man he was.

The moment was short lived. Jones tested positive for turinabol and was stripped of the gold following a failed “B” sample. His victory was also changed to a no contest.