Latin America is certainly not my strongest area, but here are just a couple of books that may help give you a framework for your research:

The Legitimization of Violence, edited by David Apter

The Foundations of Modern Terrorism: State, Society, and the Dynamics of Political Violence, by Martin A. Miller.

The first and last chapters in Miller's book go into detail about theories of state terror, and they provide a great listing of other secondary sources you may want to look at.

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