Kentucky Derby winner Medina Spirit has reportedly died.

In an interview with Thoroughbred Daily News, the colt's owner Amr Zedan said that he died of an apparent heart attack Monday morning while on the track at Santa Anita.

The Los Angeles Times reported that a siren sounded while the horses were working out and a horse emergency van rushed to the track.

In a controversy over possible disqualification, Medina Spirit has been in the news several times since the Kentucky Derby.

After winning this year's derby, the colt tested positive for the steroid "Betamethasone" and faced possible disqualification.

Trainer Bob Baffert had said an ointment used to treat the colt for a skin condition contained the substance.

Follow-up urine testing of Kentucky Derby winner Medina Spirit has shown that a steroid present in the colt’s system came from a topical ointment and not an injection.

Staff at WLEX in Lexington, Kentucky, first reported this story.