In the 1960s he wrote hundreds of articles for major publications about such topics as education in rural Puerto Rico, labor trouble on the San Juan waterfront, small factories in the Puerto Rican town of Aibonito, poverty in the Puerto Rican interior, guerrillas in Colombia, economic development in Bolivia, mining in Bolivia, violence in Nicaragua, the Duvalier regime in Haiti, political assassinations in the Dominican Republic, Maoist guerrillas in Peru, guerrillas in Venezuela, guerillas in Guatemala, church-state relations in Castro's Cuba, the detention of Juan Perón in Rio de Janeiro, and social tensions in Ciudad Juarez. He was the first to disclose the CIA's role in the 1961 assassination of Dominican dictator Rafael Trujillo and the first to report in detail on the peasant revolts in southern Peru. His reports on human rights issues include "Slaughter in Guatemala" [The New York Review of Books, May 20, 1971] and "Santo Domingo: The Politics of Terror" [The New York Review of Books, July 2, 1971].