How did Francisco Franco use secret police?

Francisco Franco utilized secret police, primarily through the Servicio de Información Militar (SIM) and later the Brigada Político-Social, to suppress dissent and maintain control during his regime in Spain. These agencies were instrumental in tracking, arresting, and interrogating political opponents, leftist activists, and anyone deemed a threat to his authoritarian rule. Their tactics included surveillance, intimidation, and torture, fostering a climate of fear that stifled opposition and ensured loyalty to Franco's government. This pervasive use of secret police helped consolidate Franco's power and suppress any potential challenges to his authority.