Kentucky Derby first Medina Spirit collapses and dies after Santa Anita workout

This year's Kentucky Derby first-past-the-post Medina Spirit has died after suffering a suspected heart attack following a workout at Santa Anita on Monday morning.

The Bob Baffert-trained three-year-old, whose victory in the 'run for the roses' at Churchill Downs in May remains in doubt having tested positive post-race for betamethasone – a therapeutic medication which is banned on raceday – had a five-furlong exercise at the track but collapsed fatally shortly after completing it.

Kentucky Derby winner under scrutiny after positive post-race test

Medina Spirit was last seen finishing second behind Knicks Go in the Breeders' Cup Classic at Del Mar last month and the Amr Zedan-owned colt was being aimed at an ambitious tilt at the Saudi Cup in February.

The California Horse Racing Board's equine medical director Jeff Blea confirmed that a full post-mortem examination will take place on Medina Spirit to fully establish his cause of death.

Medina Spirit: finished first past the post in the Kentucky Derby in MayCredit: Tim Nwachukyu (Getty Images)

He told US racing website the Paulick Report: "I spoke to the attending veterinarian and when they got to him on the track he had already died. I'm not sure where on the track it happened, but it was post-wire.

"I will have them draw blood and pull hair and will try to get urine for testing. He'll go out to UC Davis in San Bernardino, California, for a full and comprehensive necropsy including toxicology, forensics and tissue sampling. We will take a close look at the heart to try to identify the cause of death."

Bob Baffert and Medina Spirit owner file lawsuit over Kentucky Derby test result

Medina Spirit's death comes after Baffert's legal team released a statement on Friday claiming tests by a New York Laboratory had indicated that the horse tested positive for the banned raceday substance following the Kentucky Derby not through an injection, but because of an ointment used to treat a skin rash.

As well as winning the Kentucky Derby and finishing second in the Breeders' Cup Classic, Medina Spirit finished third in the Preakness Stakes and won the Grade 1 Awesome Again Stakes, earning $3,545,200 in his nine-race career.

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