They are Gerardo Hernández, Ramón Labañino, Antonio Guerrero, Fernando González and René González.
The Five were falsely accused by the U.S. government of committing espionage conspiracy against the United States, and other related charges.
But the Five pointed out vigorously in their defense that they were involved in monitoring the actions of Miami-based terrorist groups, in order to prevent terrorist attacks on their country of Cuba.
The Five’s actions were never directed at the U.S. government. They never harmed anyone nor ever possessed nor used any weapons while in the United States.
http://www.freethefive.org/whoarethefive.htm