sentences:  In addition to working with the regular security forces, Argentine military advisors as well as a squadron of the Batallón de Inteligencia 601 worked directly with the Lucas government's paramilitary death squads, most notably the Ejercito Secreto Anticommunista (ESA).Technical support from Argentina played a crucial role in the success of the army's urban counterinsurgency campaign carried out in Guatemala City in July 1981.By way of the Guatemalan military's new computer service (installed by Tadiran Electronics Industries Ltd. of Israel), Argentine advisors introduced a data analysis system developed during the "Dirty War" in Argentina, which was used to monitor electrical and water usage to pinpoint the coordinates of guerrilla safe-houses.