(CNN) -- Hot on the heels of the eight-year ban handed out to Mahmood Al Zarooni for drugging his race horses another bombshell could be set to hit the beleaguered sport.
Trainer Gerard Butler, who runs the Egerton House Stables, has admitted to a British newspaper that he is facing a ban for injecting his thoroughbreds with anabolic steroids to treat injured joints after assurances from veterinary professionals.
The British Horseracing Authority (BHA) confirmed on their official website they are investigating Butler, who is also based in the English town of Newmarket, and that samples taken from his yard had tested positive.
Just last week the BHA handed down an eight-year ban to Al Zarooni after 15 horses from the world famous Godolphin stables, owned by Sheikh Mohammed bin Rashid Al Maktoum, the ruler of Dubai, were found to have been given banned drugs.
The 37-year-old Al Zarooni admitted a "catastrophic error" in administering the prohibited anabolic steroids -- ethylestranol and stanozolol -- to the animals, all of which have been banned from racing for six months.
Butler told The Independent newspaper he thinks around 100 horses have been given the same drugs at the headquarters of British flat racing and called the incident "an unpardonable misjudgement."
He said he had given four horses at his yard a product called Sungate, which is used to treat joints, but was so sure of its validity he entered it into his official medical records which were then sent to the BHA.
"It did not cross my mind that there could be any problem with this medication," he was quoted as saying by The Independent.
"And, judging from the fact that the BHA said nothing about it when they saw my medical book, it does not seem to have crossed their minds, either.
"Little Black Book ran on 4 August, and won a couple of weeks later, so they would have known he was clearly in training at the time.
"In the medical book, I signed that I had authorized use of the drug, and my vet had countersigned for its administration. Sungate had for some time been widely used in their practice, with very beneficial results for joint injuries."
Butler runs a small stable compared to the Godolphin outfit but has had success with Elusive City and Compton Admiral, while his small U.S based operation helped Pachattack finished third in one of the country's most prestigious fillies' races -- the Breeders' Cup.
The BHA's statement read: "In light of reports and speculation today, and because of recent events regarding horses formerly trained by Mahmood Al Zarooni, it is felt necessary to confirm that a separate investigation is being held into a number of positive samples obtained from horses at Gerard Butler's yard, following a testing in training visit on 20th February.
"While conscious of the need not to prejudice the outcome of the current inquiry, the investigation has established that the source of the positive samples was a veterinary product, licensed in the EU and legally imported for use by a veterinary practice, the initial administration of which was recommended by a vet.
"This investigation remains ongoing and a number other parties have been and will be interviewed, including representatives of the veterinary practice in question. One of the objectives of this investigation is to clarify the extent to which this product has been distributed and administered to horses in training.
"Immediately following the results of the testing in training, the BHA, in conjunction with the National Trainers Federation, notified trainers that the product in question contains an anabolic steroid and should not be used on any horse in training."