Diaz-Balart was said to have killed himself Thursday morning after months of treatment for a "deeply depressed state," according to official website Cubadebate.
Among his own offspring, Castro only publicly recognized Fidelito, the angel-faced, blond boy from revolution-era photographs who caused double-takes because he resembled his father. As an adult he rose to the top post at Cuba's Atomic Energy Commission before his father removed him for unpublicized reasons in the early 1990s.
Diaz-Balart was born in 1949 and brought to the United States in the 1950’s after his mother divorced Castro. While in Mexico preparing for the guerrilla war, Castro persuaded Mirta to send Fidelito for a two-week visit, then refused to send him back.