Toby Sheets, a longtime horse trainer who worked alongside Hall of Famer trainer Steve Asmussen, was mysteriously found dead in Mathraki, a Greek island, on Sunday. 

"He did pass away in Greece," Greg Sheets, Toby’s cousin, told Thoroughbred Daily News. "As of right now, that’s all we know. The family is trying to figure out what happened."

Sheets was 55 years old. 

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Sheets’ death comes as Greek Islands have had multiple mysterious deaths in recent weeks. Seven total tourists have been found missing or dead this month alone, though most of them have been hikers. 

A heat wave could be the reason behind some of the deaths, as temperatures have hit 100 degrees in parts of the country. 

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The cause of Sheets’ death was not disclosed. 

The island Sheets was on has a population of 100 people, and is west of Corfu, an island that attracts more tourists. Mathraki is only 1.2 square miles. 

"Today was a part of our stable for many years, including our Belmont Stakes win with Creator, as well as his expert handling of Haynesfield among others," Asmussen said, via Thoroughbred Daily News. "He will be deeply missed by his family and many friends."

Sheets was first reported missing on Thursday and was last seen alive on Tuesday at a café with two other tourists, according to CBS. The two female tourists have since left the island. 

"He was found in the surf on the beach at a spot which had already been searched, so it seems he was washed out of the sea in the past 24 hours," Mathraki Deputy Mayor Spyros Argyros told The New York Times. 

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