Federal prosecutors have told a Bay of Pigs veterans association president that he is a suspect in the murder here of former Chilean Ambassador Orlando Letelier, the leader of the veterans group said yesterday.

Roberto Carballo, who heads Brigade 2506, an association of anti-Castro Cubans who participated in the abortive Bay of Pigs invasion in 1961, said in a telephone interview from Miami that he was told he was suspected in the Letelier killing when he appeared before a grand jury here last month. Carballo said the accusation is false.

"They did regard me as a suspect in it," Carballo said in the interview. "They thought that I was involved in it directly."

Carballo said he was warned by Assistnat U.S. Attorney Eugene M. Propper that he is suspected in Letelier's bombing death last Sept. 21. Propper is coordinating the U.S. probe into the murder of Letelier.

"This is ridiculous. It's not true at all," Carballo added.

Propper said he would have "absolutely no comment" on Carballo's statements or on the continuing investigation.

The Washington Post reported yesterday that, according to informed sources, federal prosecutors now have evidence leading them to believe that Letelier's killing was carried out by anti-Castro Cubans directed by persons in Chile.

Identities of those suspected in the murder have not previously been made public. Carballo and five other members of the Bay of Pigs veterans' group are known, to have appeared as grand jury witnesses here. Their appearance before the grand jury does not it itself indicate that they are suspects in the investigation.

Carballo said in the telephone interview yestreday that the five other members of his group who testified before the grand jury were asked whether they had participated in Letelier's assassination. He said all five denied any involvement in Letelier's death. He declined to identify the other Bay of Pigs veterans who appeared before the grand jury.

Letelier, 44, former ambassador to the United States and foreign minister and minister of defense in the Marxist government of the late Chilean President Salvador Allende, was killed when a bomb exploded beneath his car as he drove along Embassy Row here. One other passenger, Ronni K. Moffitt, also died in the explosion.

Carballo also said during yesterday's interview that Assistant U.S. Attorney Propper had felsely accused him of involvement with the Chilean intelligence agency, known as DINA. "I do not know anyone from DINA. I have not had any offer from DINA in any regard," Carballo said.

Many critics of the current Chilean military junta have charged that Letelier was killed by DINA agents. The Chilean government has denied any link to Letelier's death and has condemned his murder.

Carballo said he testified before the grand jury, under questioning by Propper, that he had met during June in the Dominican Republic with Orlando Bosch, leader of an anti-Castro umbrella organization, known as CORU, the Coordination of United Revolutionary Organizations.

Bosch, wanted for questionig by federal prosecutors in the Letelier investigation, is being held by Vnezuelan authorities in connection with the Oct. 6 crash of a Cuban airliner, in which 73 persons died. The plane is reported to have been blown up.

Carballo said he severed Brigade 2506 members as a "scapegoat" in the Letelier investigation. "We don't support that. We have spoken clearly against terrorist acts, especially in the United States," Carballo said.