Complex sentence: The DEA manages to track the movements of people going in and out of La Catedral and observe that two of Pablo's closest associates, Moncada and Galeano, entered the prison but never left.
Split into simpler sentences: The DEA manages to track the movements of people going in and out of La Catedral. They observe that two of Pablo's closest associates, Moncada and Galeano, entered the prison but never left.