Jamie Richards' record of six training wins in a day at Ellerslie is in jeopardy after one of his Boxing Day winners returned an irregularity in a post-race test.
But the champion trainer's licence is not believed to be in danger as racing investigators suspect a case of cross-contamination.
Richards trained an Ellerslie record six winners at the Boxing Day meeting but one of them, Vamos Bebe, has returned a post-race urine sample irregularity, which the Herald understands is to morphine, after her win in the Listed Hallmark Stud.
The irregularity, which is not officially classed as a positive swab until after the B-sample is tested and an investigation completed, is a double blow for the owners of Vamos Bebe as she is now almost certain to lose the black-type win.
Disqualification of a horse is almost always the outcome after proven drug irregularities even when no foul play is suspected.