BY ALFONSO CHARDY

 A key witness against accused torturer Eriberto Mederos, who allegedly administered electroshock treatment to Cuban political prisoners at a hospital in Havana, has died.

 Eugenio de Sosa Chabau, 85, a former classmate of John F. Kennedy at an exclusive Connecticut prep school in the 1930s, claimed he was tortured with the treatments after Cuban officials imprisoned him at the Havana Psychiatric Hospital because he smuggled a warning to Kennedy in 1962 saying Moscow had shipped or was about to ship nuclear missiles to Cuba.

 Federal officials said they did not expect de Sosa Chabau's death from cancer to affect the government's case against Mederos. Federal prosecutors hope to convince a jury to revoke his U.S. citizenship on the grounds he lied to the U.S. Immigration and Naturalization Service about his past.

 Though de Sosa Chabau was a key witness because of his Kennedy connection and prominence in the Cuban exile community, there are at least 10 other witnesses who can still testify for the government, federal officials said.

 A resident of Coral Gables, de Sosa Chabau died New Year's Day while visiting a daughter in Dallas, his younger brother, Juan de Sosa, 74, said Thursday from his home in New Port Ritchey, Fla.

 BURIAL TODAY

 De Sosa Chabau was to be buried in Miami today at Woodlawn Park cemetery on Southwest Eighth Street in Little Havana following a 9 a.m. Mass at St. Raymond Catholic Church, said son-in-law Alberto Jorge.

 ``He was a man of a lot of action, who loved his family very much and who was very religious and had great moral character,'' said Juan de Sosa. ``It's a great loss.''

 De Sosa Chabau's allegations came to light in 1991 when The Politics of Psychiatry in Revolutionary Cuba by Charles J. Brown and Armando M. Lago was published. The book, which featured a segment on de Sosa Chabau, portrayed electroshock treatment at the hospital as torture.

 De Sosa Chabau was the scion of one of Cuba's oldest families whose wealth and prominence enabled their child to attend what was then the all-boys prep school Choate -- now Choate Rosemary Hall -- in Wallingford, Conn. Kennedy and de Sosa Chabau were among the 112 members of the class of 1935.

 After graduating and returning to Cuba, de Sosa Chabau went on to own a sugar mill and briefly helped manage Havana's leading newspaper, Diario de la Marina, before Fidel Castro seized power.

 IMPRISONMENT

 But his main claim to prominence came in the 1990s when his imprisonment at the psychiatric hospital was disclosed. It was in interviews with The Herald last year that he said his attempt to warn Kennedy about the nuclear missiles had landed him at the psychiatric hospital.

 De Sosa Chabau was initially jailed in late 1959, accused of plotting against Castro. In all, he spent almost 21 years in Cuban jails as a political prisoner, nine months of which were at the psychiatric hospital widely known in Cuba as Mazorra.

 While at Mazorra, de Sosa Chabau said he underwent 14 sessions of electroshock treatment at Mederos' hands.

 David Rothman, Mederos' attorney, did not return a call to his office.

 Mederos has acknowledged delivering electroshock -- but only as a medical procedure ordered by doctors, not as torture. He was arrested Sept. 4 by INS agents on charges he lied about torturing Cuban political prisoners with electroshock treatments.

 Besides being a witness against Mederos, de Sosa Chabau also had joined other Cuban exiles in filing a 52-page complaint accusing Fidel Castro of crimes against
 humanity. Those charges have been filed in Belgium.

 De Sosa Chabau is survived by four daughters -- Lolita, Regina, Josefina and Maria Eugenia, and a son, Eugenio. A fifth daughter, Sylvia, died of cancer in 1992.

 He is also survived by his brother Juan and sister Martha de Sosa de Rivero, as well as 17 grandchildren and 31 great-grandchildren.

                                    © 2002