dense and rather regular network; even at that time suburban borough of Puente de Vallecas hosted 17 such places. Among 5 checas with the largest number of victims recorded, Checa San Bernardo, Checa Lista and Checa Santa Engracia were located in the very centre, while Checa del Ateneo and Checa del Circulo somewhat more outside. Headquarters of CPIP, perhaps the most prominent institution of Republican repression system, was centrally located first at Calle de Alcala and then at Calle de Fomento; premises of DGS and its agendas were scattered around the Salamanca district, usually at or near Calle de Serrano. Until mid-1937 most detentions were carried out in the districts of Chamberi and Buenavista; later these areas ceased to stand out. Geographical location of execution sites changed over time. During the first months of the conflict the inmates were taken usually to the Western districts of Madrid or to its Western suburbs, especially to Aravaca in the North, large green areas of Casa de Campo in the centre and to the park known as Pradera de San Isidro in the South. It is supposed that these sparsely populated and partially rural areas were deemed more suitable for executions than more densely inhabited Eastern and Northern peripheries of the capital. However, as the Nationalist troops approached from the West, Aravaca or Casa del Campo found themselves dangerously close to the frontline and soon became the battlefield themselves, which prompted re-orientation of executions. Since October they were taking place in the East and in the South, especially in Rivas-Vaciamadrid, along Carretera de Andalusia and near Cimiterio del Este. Paracuellos de Jarama was chosen as site of the largest executions because it remained away from the frontline, because there was an easy road access from Madrid, and because local ayuntamientos were considered politically reliable, ready to organize the locals for work related to burying the bodies. Protagonists During the first few weeks of the war the person responsible for public order in Republican Spain was Sebastián Pozas Perea, the Minister of Interior; scarcely involved in local Madrid issues, he nevertheless demonstrated complacency towards the revolutionary groupings. His second in command, the DSG head José Alonso Mallol, tried to preserve integrity of state structures yet overwhelmed by events, he resigned on July 31, 1936. His replacement was Manuel Muñoz Martínez, who since early September reported already to the new minister, Angel Galarza Gago. The