Longtime horse racing trainer Toby Sheets was found dead in the Greek Islands this past week.

He was 55.

Sheets for years worked as an assistant to Hall of Fame trainer Steve Asmussen.

A number of tourists have mysteriously died on the Greek islands in recent weeks, and the circumstances of how Sheets passed are currently unknown.

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

Sheets was found dead on Mathraki, a small, little-known Greek island with a population of just 100 people.

The island is just 1.2 square miles, according to CBS, located near Corfu, a more popular tourist destination.

“Toby 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 told TDN. “He will be deeply missed by his family and many friends.”

The New York Times reported that a 55-year-old Floral Park native, who was identified by TDN as Sheets, had been last seen on Tuesday, and that his body was found on the beach on Sunday.

According to the Associated Press, the tourist had “been seen Tuesday at a cafe in the company of two female tourists who have since left the island.”

Seven total tourists, mostly hikers, have either died or gone missing in the Greek islands this month amid a torrid heat wave.