HENDERSON, Ky. (AP) — A race horse that ran in the Kentucky Downs Preview Day has died.

News outlets report a 7-year-old gelding named Sir Navigator collapsed twice Sunday after finishing fourth in the Preview Turf Sprint at Ellis Park in Henderson. The Henderson Gleaner reports the horse died while being treated on the track.

Chief State Veterinarian Bruce Howard says he thinks the death could have been caused by a heart attack, internal bleeding or heat. He says an autopsy will be needed to determine the cause of death.

Ellis Park spokesperson Jennie Rees says there are precautions in place to make sure horses are well enough to compete. The park's General Manager Jeff Hall says if Sir Navigator had shown signs of any ailment, he wouldn't have been allowed to run.