Short answers, pulled from the story.
SAVAK was officially birthed by a national security law in 1957. State media reported the intended establishment of such an agency by October 1956, but the Bureau for Intelligence and Security of the State emerged from political upheaval three years prior to its formal creation.
Major General Herbert Norman Schwarzkopf trained virtually all of the first generation of SAVAK personnel. French intelligence provided crucial assistance during these formative years while CIA officers also played a significant role in establishing the organization through funding and training.
Brute force remained supplemented by the bastinado which involved beating the soles of feet. Sleep deprivation became another standard tool used against detainees alongside extensive solitary confinement and glaring searchlights that kept inmates awake at night.
Estimates ranged from 4,000 to 6,000 members according to scholar Gholam Reza Afkhami. TIME magazine stated in February 1979 that the agency had exactly 5,000 members while some sources claimed figures as high as 30,000 or even 60,000 personnel.
SAVAK closed down shortly before the overthrow of the monarchy in February 1979. The ministry became known as VEVAK or Ministry of Intelligence and National Security of Iran following the transition marked by fear and surveillance.