JOIN USThe 26-year-old, bronze medallist in both the 10km event at the Rome worlds in 2009 and the FINA world open water champs in Canada this year, had ambitions to become the first American to medal in open water swimming at the 2012 London Olympics.
"While the causes of this death remain under investigation, FINA and the entire aquatic community address, in this moment of grief, their deepest and sincere condolences to his family, friends and to US Aquatic Sports and USA Swimming family," FINA said in a statement.
USA Swimming added that it was "deeply saddened by the death of Fran Crippen", who was a two-time US champion in the pool in the 800m freestyle event before moving into open water swimming in 2006.
"Fran was a champion swimmer but more importantly, a tremendous person, and he will be remembered for so many extraordinary qualities.
"We send our sincere condolences and deepest sympathies to the Crippen family, a family that is a treasured member of the USA Swimming family."We will continue to work with FINA, the meet host and others to determine how this tragedy occurred."