There were many people in Chile who believed that Manuel Contreras Sepulveda, the first and only head of the Directorate of National Intelligence, was the second most powerful man in the country. He was certainly one of the most feared.

Before it was dissolved last year, his agency, known as DINA, was blamed for the disappearance and torture of thousands of people as it sought to fortify the strength of the military junta and suppress its opposition, both in Chile and abroad.

As head of DINA, Contreras was answerable only to Chilean President Augusto Pinochet, with whom he reputedly was on intimate terms.

On March 21 of this year, however, as international criticism of Chile's human rights record mounted, and the investigation of Orlando Letelier's murder heated up, Contreras resigned from the Army and all government posts he had held since DINA was abolished. No official explanation for the resignation was given.

Contreras is accused in the indictment of having ordered Letelier's assassination, but the man the indictment charges with most of the plotting and supervision for the operation is Pedro Espinoza, a colonel in the Chilean army and currently commander of a garrison in southern Chile. At the time of Letelier's death, Espinoza was director of operations for DINA. Little else is known about him, though according to several sources familiar with Chilean politics, it had been widely suspected that Espinoza was in charge of stifling criticism from exiled members of the former government.

Armando Fernandez Larios, the man accused of organizing the actual assassination of Letelier, and, with Michael Vernon Townley, contacting and coordinating the activities of the Cuban exiles involved, is a captain in Chile's army.

The son of a retired Air Force general, he took part in the storming of the Moneda Palace during the 1973 coup, and now works at the Ministry of Defense in Santiago.