05/17/2013 12:51 EDT | Updated 07/17/2013 05:12 EDT

British Horseracing Authority widens doping investigation, will interview more trainers

LONDON - The British Horseracing Authority has widened the scope of a doping investigation that was launched last month after a trainer admitted to giving horses a product containing anabolic steroids.

The BHA says it believes Gerard Butler "was not the only trainer to whom the administration of Sungate was recommended" by veterinary practices.

Sungate, which is legal in Britain and is used to treat joint problems, contains the banned anabolic steroid stanozolol.

Butler was told that four of his fillies tested positive for a prohibited substance after the BHA made an unannounced visit to Butler's stable in February.

The BHA said Friday that "in order to establish the extent of the use of the product, investigating officers will be interviewing trainers who are known to use the same veterinary practice."