SHIRLEY, N.Y. (CBSNewYork) — A man has died after participating in a triathlon on Long Island Sunday morning.

According to authorities, Vincent Fleck, 69, of Mount Kisco, was rescued from the waters of Narrow Bay at Smith Point County Park in Shirley at around 7:25 a.m. after authorities noticed he was in distress.

Fleck was taken to Brookhaven Memorial Hospital Medical Center where he was later pronounced dead, police said.

Fleck was participating in the 500-meter swim section of the Smith Point Sprint Triathlon at the time of the incident.

The exact cause of Fleck’s death is still under investigation.