The marathon swimmer who disappeared during a 120-mile race in the Hudson River has been confirmed dead by his family, according to organizers.

Dr. Charles Van Der Horst, 67, of Chapel Hill, North Carolina, had been competing in the “8 Bridges Race” on Friday when he vanished near the New Jersey side of the George Washington Bridge.

A man who was watching the race from a riverbank told investigators that he saw the internationally recognized AIDS researcher and former college professor go under around 3 p.m.

“The family of [Van Der Horst] is deeply saddened to confirm the loss of our beloved Charlie,” New York Open Water, the organization that operates the 8 Bridges Race, said in a Facebook statement Sunday. “He was participating in several stages of the [river swim] when he went under at the finish of Stage 6.”

The race had started on June 8 — approximately 100 miles away — at the Rip Van Winkle Bridge between Hudson and Catskill.

“Charlie exemplified living life to its fullest,” the organizers said, showing off a photo of him jumping into the Hudson.

“He put all of his passion and zest into everything he did, from his love of his family, friends and community, to his swimming to his work on social justice and in the medical field. At this time we ask that you respect our wishes for privacy as we mourn this tragic loss.”