Queensland Racing stewards ordered the scratching of a fancied runner at Eagle Farm as they opened an inquiry into trainer Chris Munce.
Lady Brahmos was withdrawn from the Gallopers Sports Club Handicap (1200m) on Saturday following a without notice stable inspection at Munce's Eagle Farm base a day earlier.
The inspectors allegedly discovered that Lady Brahmos had been recently administered an injection, which is against the rules a day out from a race.
Lady Brahmos had been favourite for the race prior to her withdrawal.
A swab has been taken from the mare for analysis and Munce's sole runner at the Gold Coast on Saturday, Lucky Time, has also been tested as a precaution.