SANTA ANA, Calif -

The Orange County Coroner's Office is investigating the death of a college athlete who just last month helped the University of Southern California water polo team win a national championship.
   
Nineteen-year-old Jon Walters, a freshman at USC, died of a heart attack at a hospital Wednesday, his father, Bill, tells the Orange County Register.
   
Bill Walters says his son had been fighting pneumonia and kidney failure after falling into a coma on Jan. 1.
   
The coroner's office says the cause of death is under investigation.
   
Jon Walters was on the USC water polo team that won the National Collegiate Athletic Association championship in December.
   
Walters, who played center, was a member of the U.S. junior team while at Mater Dei High School in Santa Ana.
   
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