Original sentence: Human-rights groups claim that Ríos Montt, a staunch anticommunist who has had ties to the United States for over five decades (via the Pentagon's School of the Americas), the CIA, presidential administrations, and the evangelical religious right), has been among the bloodiest strongmen in Latin American history during his time as President, although he himself strenuously denies that he knew anything about the massacres that were taking place under his rule
Edited sentence: Human-rights groups claim that Ríos Montt, a staunch anticommunist who has had ties to the United States for over five decades (via the Pentagon's School of the Americas), the CIA, presidential administrations, and the evangelical religious right), has been among the bloodiest strongmen in Latin American history