The American event horse Le Samurai has been put down following advice from vets.

Le Samurai was being treated at the Hagyard Equine Medical Institute in Lexington after going badly lame at the Rolex Kentucky three-day event on 28 April. His rider, Amy Tryon, is now at the centre of an investigation by the International Equestrian Federation (FEI).

At the weekend, the horse’s owners, Jerome and Rebecca Broussard, announced at that Le Samurai, also known as “Sparky”, had been put down.

They said: “From the outset we have been determined to give this magnificent horse the best veterinary treatment available, but only so long as the continuation of that treatment remained consistent with Sparky’s best interests.

“Regrettably, the veterinarians treating him have advised us that a successful outcome is not possible.”

Le Samurai finished the cross-country at Rolex Kentucky, but afterwards was found by the course vet to have “lost the supporting ligaments in his front leg”. The event’s ground jury disqualified Miss Tryon, and referred the case to the FEI judicial committee.

The story has caused huge debate on website forums around the world.