Medina Spirit, whose 2021 Kentucky Derby win is under dispute, collapsed and died after a routine workout on Monday morning at the Santa Anita racetrack in Southern California.

The three-year-old colt died suddenly from what appears to have been a cardiac event, according to the on-site veterinary team that attended to him.

"My entire barn is devastated by this news," Bob Baffert, the horse's trainer, said in a statement. "Medina Spirit was a great champion, a member of our family who was loved by all, and we are deeply mourning his loss. I will always cherish the proud and personal memories of Medina Spirit and his tremendous spirit."

Medina Spirit's victory at the Kentucky Derby earlier this year became clouded after a post-race drug test found the drug betamethasone. The steroid is commonly used to treat pain and inflammation in horses, but is considered an illegal substance on race days.

Churchill Downs, the Louisville home of the Kentucky Derby, suspended Baffert after Medina Spirit failed a second drug test.

Baffert is suspended for two years, and any trainer affiliated with his stable cannot enter horses in races operated by Churchill Downs.

The Santa Anita Park veterinary team immediately took blood, hair and urine samples from the horse and sent them to the California Horse Racing Board. A full necropsy will be performed, as per protocol in California.

Santa Anita has faced scrutiny in the past for spikes in thoroughbreds deaths due to injuries from racing or training. The track shut down for most of March 2019 after 23 thoroughbreds died in a span of three months.

Tien Le is an intern on NPR's News Desk.

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