Complex sentence: In October 1959, the United States sent a "Special Survey Team", composed of counterinsurgency experts, to investigate Colombia's internal security situation, due to the increased prevalence of armed communist groups in rural Colombia which formed during and after "La Violencia".
Split into simpler sentences: In October 1959, the United States sent a "Special Survey Team", composed of counterinsurgency experts, to investigate Colombia's internal security situation. This was due to the increased prevalence of armed communist groups in rural Colombia which formed during and after "La Violencia".