The Times reported that the thoroughbred tested positive for scopolamine, a banned performance-enhancer, after winning the Santa Anita Derby on April 7, 2018.
The news could have massive ramifications on the Australian breeding industry with Justify standing at Coolmore Australia after the breeding operation purchased the colt for $60m United States dollars.
Justify won the Kentucky Derby, Preakness and Belmont Stakes as a three-year-old before Coolmore bought his breeding rights for $US60 million after his retirement.
The Santa Anita Derby win earned Justify a spot in the Kentucky Derby. "I think this horse, what he did today, shows us his natural talent", Baffert said.
However, the Times said California regulators waited until April 26, nine days before the Kentucky Derby, to inform Bob Baffert, Justify's Hall of Fame trainer.
After Justify won the Triple Crown, Drape says that the California Horse Racing Board disposed of the inquiry and decided that "the positive test could have been a result of Justify's eating contaminated food". "That's impossible. Well, that's not impossible, that would have been careless and reckless for us to tell an investigator what usually takes you two months, you have to get done in five days, eight days".
"There was no way we could have come up with an investigative report prior to the Kentucky Derby", Baedeker told the Times. "We weren't going to do that", Drape quoted Baedeker as saying.
In addition, the California board's medical director said of scopolamine in 2016 that the chance of "getting a positive from environmental contamination is rather low".
In the past, positive tests for scopolamine have resulted in disqualifications, purse reimbursements, fines and suspensions, according to the report.
California's racing board has come under fire this year because of the deaths of 30 racehorses at Santa Anita Park since the day after Christmas.
He added that the board would have a further response on Thursday.
The 2018 campaign was an historic one for Justify, who became the 13th Triple Crown victor, and the second in four years, following American Pharoah's tremendous run in 2015.