The AFL anti-doping tribunal has found former Essendon sports scientist Stephen Dank guilty of 10 charges.
But the tribunal also was not comfortably satisfied on 21 other charges that Dank was facing.
Most of the charges related to the 2012 Essendon supplements program.
On March 31, the same tribunal found 34 current and past Essendon players not guilty of doping offences.
“The breaches include trafficking, attempting to traffick and complicity in matters related to a range of prohibited substances,” the league said in a statement.
The three-man tribunal’s verdict was unanimous and it will sit again on May 5 to decide penalty.
They acquitted Dank of administering Thymosin beta-4 to Essendon players in 2012.
The 34 players were found not guilty of having taken the same banned substance.