By  JIM McGEE
Herald Staff Writer

    Miami's tenacious anti-Castro movement is in disarray.  It is crippled by internal dissension and discredited by failure.  It is riddled with Castro informants.
    The same exile groups that loudly and sometimes violently express their hatred of Castro are closely monitored - and in some cases manipulated - by Castro spies. The spies have been in place for years.
    Long ago, Castro boasted about his intelligence network.
    His spies, posing as "anti-Castroites," slip into "the ranks of the enemy" and sabotage the exiles, he declared in a 1965 speech.
    Castro wasn't just blowing smoke - from his cigar or otherwise.
    "The Cubans have all the exile organizations and even the terrorist organizations ... thoroughly penetrated," said Wayne Smith, once a State Department specialist on Cuban affairs.
    "I can only say they [Cuban agents] have infiltrated most, if not all, anti-Castro organizations," said Arthur Nehrbass, former head of the FBI office in Miami, now chief of the Metro-Dade Organized Crime Bureau.
    This is no big surprise to the exile groups:  Brigade 2506, Alpha 66 and Abdala.  They've all had bad experiences.
    Carlos Rivero-Collado's credentials in the anti-Castro movement were impeccable.  He was an original member of Brigade 2506 and a close associate of the Cuban Nationalist Movement.
    In 1972, Rivero helped organize the Pragmatistas, a vicious exile group.  They were linked to terrorist attacks and extortions in Little Havana that angered both the Cuban and non-Cuban communities.
    Unworried, unscathed - perhaps amused - was the Castro government.
    Rivero returned voluntarily to Cuba in 1975.  He told Castro's intelligence officers what he knew about Miami's terrorist underground - and the friends he deceived.
    "They [the Pragmatistas] were so thoroughly infiltrated, " said David Nye, a Miami police specialist in Cuban terrorism, that they were "...more an arm of the Cuban government than an anti-Castro group."
    Alpha 66 had its infiltration problems, too.
    Mario Estevez, a Castro spy who arrived here in the Mariel boatlift, got into Alpha 66 because a relative belonged.
    Alpha 66 liked him.  It put him in charge of its attack boats.  And Estevez managed to sink two of them.
    One reason Castro spies have such an easy time is the absence of retaliation by U.S. authorities.  No Little Havana infiltrator has ever been prosecuted for espionage.
    That's because infiltrators rarely jeopardize U.S. security.
    "The presence of Cuban agents in anti-Castro organizations is not among the highest priorities of things this FBI has to do," said Jim Freeman, second-in-command of the Miami FBI office.
    "You have to balance these things, " said ex-FBI agent Nehrbass.  "...If the target is not an espionage one against the U.S., then they are really not doing a large amount of damage to U.S. security."
    The FBI considers Miami's anti-Castro terrorist bombings a more pressing problem.
    Interestingly enough, that sometimes leads to an unspoken symbiosis between the FBI and Cuban intelligence.  They share the same goal:  Neutralize the terrorists.
    "There is a certain degree of convergence of interest," Nehrbass said.
    Miami FBI agents identify many of the Cuban spies in Miami, but, as often as not, try to recruit them as informants.
    A still-secret FBI memorandum explains why:  "These informants are in a position to develop information regarding anti-Castro terrorist activities, as this is an objective of the Cuban intelligence service."
    The 1980 Mariel boatlift gave Cuban intelligence a golden opportunity to inundate Miami with infiltrators.
     The exact number of Mariel spies is unknown.  Uncorroborated congressional testimony fluctuates wildly, with estimates from 300 to 3,000.
    The FBI won't cite any figure.  It doesn't want to tell the Castro government what it knows.
    Mario Estevez spoke candidly about how easily he infiltrated Alpha 66.
     "This is a very free country," he said.  "The don't ask you for anything here."