The Miami Herald explains that the FBI was reluctant to arrest and prosecute Americans who spied for Cuba until after Cuba shot down two Brothers to the Rescue planes, killing four Americans. It also indicates that Cuban intelligence was badly damaged when Army General Arnaldo Ochoa was executed for drug running and the Ministry of  Interior, the agency in charge of Cuba's security was purged.

Cuba's firing-squad executions of Gen. Ochoa, MININT Col. Tony de la Guardia and two other security force officers on charges of drug running. Some 300 MININT officers were purged, and many were replaced by military officers with little experience in intelligence. Several DI and DCI officers defected and provided valuable information to Western intelligence services.

U.S. spy-catchers say Cuban intelligence focuses its trolling for potential American spies on the four Washington-area universities whose international studies programs regularly send their graduates to key positions throughout the U.S. government -- Johns Hopkins, Georgetown, American and the University of Virginia. ''The Cubans fish in a small pond,'' said one. [snip]

But whatever the results of the damage assessment, within the U.S. intelligence community there's little doubt that the Myers couple was NOT the last of the Cuban spies.

Chris Simmons, a retired Pentagon expert on Cuban Intelligence who helped uncover Montes' spying, estimates that Havana maintains approximately 250 agents and agent-handling officers in the United States [snip]

Based on past Cuban ''tactics, techniques, and procedures,'' Simmons said, the 250 would include six to nine senior agents within the U.S. government similar to Montes, more than a dozen in academia and 30-36 under diplomatic cover at Cuban missions in Washington and New York.