The Iditarod Trail Committee has released a statement in regards to the banned substance found in several dogs that competed in March's race.
While the "musher" will remain unnamed, the committee announced that the painkiller, tramadol was the substance that the dogs' tested positive for.
Tramadol is an analgesic that is used to control moderate to severe pain.
It is listed as a Class Four opioid drug.
According to the I-T-C, the drug could have been administered from a time period of 15 hours till the drug test was taken in Nome.
The urine samples were taken six hours after the race.