According to officials of Racing Victoria, Justdoit, which was trained by Luke Oliver, tested positive for a prohibited substance following the Donate to RDA Australia event at Flemington on August 3.
It was later revealed that the sample contained traces of methamphetamine.
Oliver was informed about the positive test at the start of September.
He said that he was surprised by the news, and he was helping the stewards with their investigation.
He also admitted that it had been difficult for him and his staff, as well as the owners of the mare, to deal with.
The ARL’s Forensic Laboratory informed RV that it detected traces of methamphetamine in the sample taken from Justdoit.
However, the organization noted that there was no evidence suggesting that the substance was used for therapeutic purposes.
The substance used in racing is prohibited under the Australian Rules of Race.
The stewards first informed Oliver about the positive test on September 5.
He was then informed of the results of the follow-up test on September 27.