More than a month after prosecutors declared them ``John Does,'' federal authorities are still unable to identify three accused members of a Cuban spy ring that operated for several years in South Florida.

Arrested Sept. 15 as Manuel Viramontes, 31, Luis Medina III, 30, and Ruben Campa, 33, all claiming U.S. citizenship, the U.S. Attorney's office classified them as John Doe 1, 2 and 3, in their subsequent Oct. 2 indictment that alleges they were agents of the government of Fidel Castro.

``Only they and Fidel know who they really are,'' said John Schlesinger of the U.S. Attorney's Office on Friday.

``They're still being carried as John Does,'' added FBI Special Agent Mike Fabregas.

Prosecutors argued in court that all three men are actually masquerading in the identities of U.S. citizens who died as young boys in Texas, presumably people of Hispanic heritage who would not have relatives in South Florida. Not only did they allegedly assume their names, but they supposedly took their birthdays as well, a mechanism that allowed them to obtain birth certificates.

Investigators, they said, believe the three men are actually Cuban citizens posing as Americans.

In the case of the man who calls himself Viramontes, Deputy U.S. Attorney Caroline Heck Miller alleged in court that federal agents believe from their analysis of his personal documents that he has a wife of 10 years still living in Cuba. Further, she said, FBI wiretaps of his home determined that, while he spoke in Spanish on the telephone he assumed a Puerto Rican accent, but inside his home he spoke with a Cuban accent.

And in the case of the man who calls himself Medina, Deputy U.S. Attorney Guy Lewis alleged in court that he is in fact a major in the Cuban military whose real first name is Ramon. Authorities surmised this by watching videotape of the suspect, which they believed was shot in Cuba, in which people call him ``Ramon.''

Defense attorneys for two of the men -- Paul McKenna for John Doe 1 and Eric Cohen for John Doe 2 -- say their clients steadfastly maintain that they are who they claim to be, Viramontes and Medina. Federal public defender Joaquin Mendez, who represents John Doe 3, could not be reached for comment despite repeated attempts.

At issue is, if the men are not U.S. citizens, how and when they arrived in South Florida -- and who helped them.

Did they come with valid U.S. immigration documents and then assume new identities? Or did they arrive illegally -- perhaps during the 1994 rafter crisis when Cuban migrants overwhelmed South Florida's shores?

Prosecutors consider the three men to be leaders of the 10-member ring that allegedly snooped on Cuban American interest groups and tried to monitor the Miami-Dade activity at the Pentagon's U.S. Southern Command headquarters, which controls all U.S. troop activity in the Southern Hemisphere.

The trio face a September 1999 trial, along with Rene Gonzalez, 42, and Antonio Guerrero, 39, who were both born in the United States. All are accused of conspiring to act as agents of a foreign government, Cuba, without registering with Attorney General Janet Reno. John Does 1 and 2 and Guerrero are also accused of conspiring to pass along U.S. national defense information to Cuba.

Five other people arrested as ring members have pleaded guilty to lesser charges, carrying punishments ranging from five to 10 years in prison. Sentencing is expected in September 1999 as well. Their guilty plea agreements suggest they are cooperating with federal authorities as they develop their cases against the other five.

All 10 people, two of them women, are in jail.