The eldest son of late Cuban revolutionary leader Fidel Castro committed suicide aged 68 after being treated for months for depression.

Cuban government sources confirmed that Fidel Castro Diaz-Balart,  a nuclear scientist known as “Fidelito” because of his close resemblance to his late father, died on Friday morning following treatment “for a deep state of depression by a group of doctors.”

His father, who built a Soviet-aligned Communist state just off the coast of the United States at the height of the Cold War, died on November 26, 2016,  aged 90.

Through his mother, the younger Castro was the cousin of some of Castro’s fiercest enemies in the Cuban-American exile community, including US Representative Mario Diaz-Balart and former Congressman Lincoln Diaz-Balart.

Cuba scholars say his mother took the young Fidelito to the US at the age of five after she announced her intention to divorce his father, who was serving a prison sentence for a 1953 attack on the Moncada military barracks in Santiago.

Castro was able to bring Fidelito back to Cuba after the 1959 revolution. A multilingual nuclear physicist who studied in the Soviet Union, Castro was head of Cuba’s national nuclear program from 1980-1992 and spearheaded the development of a nuclear plant until his father fired him.

Fidelito had been working for his uncle, President Raul Castro, as a scientific adviser to the Cuban Council of State and Vice-President of the Cuban Academy of Sciences at the time of his death.