A U.S. Army colonel working for the CIA was sent to Persia in September 1953 to work with General Teymur Bakhtiar, who was appointed military governor of Tehran in December 1953 and immediately began to assemble the nucleus of a new intelligence organization. The U.S. Army colonel worked closely with Bakhtīār and his subordinates, commanding the new intelligence organization and training its members in basic intelligence techniques, such as surveillance and interrogation methods, the use of intelligence networks, and organizational security. This organization was the first modern, effective intelligence service to operate in Persia. Its main achievement occurred in September 1954, when it discovered and destroyed a large communist Tudeh Party network that had been established in the Persian armed forces
In March 1955, the Army colonel was "replaced with a more permanent team of five career CIA officers, including specialists in covert operations, intelligence analysis, and counterintelligence," who "trained virtually all of the first generation of SAVAK personnel." In 1956 this agency was reorganized and given the name Sazeman-e Ettela'at va Amniyat-e Keshvar (SAVAK). In 1960/61 the CIA trainers left and were replaced by a team of instructors from the Israeli Mossad. These in turn were replaced by SAVAK’s own instructors in 1965.
SAVAK had the power to censor the media, screen applicants for government jobs, "and according to reliable Western source , use all means necessary, including torture, to hunt down dissidents."
After 1963, the Shah expanded his security organizations, including SAVAK which grew to over 5300 full-time agents and a large but unknown number of part-time informers.
The agency's first director, General Teymur Bakhtiar, was dismissed in 1961 and later became a political dissident. In 1970 he was assassinated by SAVAK agents, disguised to look like an accident.
Hassan Pakravan, director of Savak from 1961-1965, had an almost benevolent reputation, for example, dining with the Ayatollah Khomeini while Khomeini was under house arrest on a weekly basis, and later intervened to prevent Khomeini's execution, on the grounds it would "anger the common people of Iran". After the Iranian Revolution, however, Pakravan was among the first of the Shah's officials to be executed.
Pakravan was replaced in 1965 by General Nematollah Nassiri, a close associate of the Shah, and the service was reorganized and became increasingly active in the face of rising Shia and Communist militancy and political unrest.
Abrahamian estimates that SAVAK (and other police and military) killed 368 guerillas between 1971-1977 and executed something less than 100 political prisoners between 1971 and 1979 - the most violent era of the SAVAK's existence.
One well known writer was arrested, tortured for months, and finally placed before television cameras to `confess` that his works paid too much attention to social problems and not enough to the great achievements of the White Revolution. .... By the end of 1975, twenty-two prominent poets, novelist, professors, theater directors, and film makers were in jail for criticizing the regime. And many others had been physically attacked for refusing to cooperate with the authorities.
By 1976, this repression was softened considerably thanks to publicity and scrutiny by "numerous international organizations and foreign newspapers." In 1976, Jimmy Carter was elected President of the United States and he "raised the issue of human rights in Iran as well as in the Soviet Union. Overnight prison conditions changed. Inmates dubbed this the dawn of `jimmykrasy.` .... "
According to Polish author Ryszard Kapuściński, SAVAK was responsible for
Sources disagree over how many victims SAVAK had and how inhumane its techniques were. For example, according to articles in Federation of American Scientists and TIME magazine, SAVAK "tortured and murdered thousands of the Shah's opponents. It's "torture methods included electric shock, whipping, beating, inserting broken glass and pouring boiling water into the rectum, tying weights to the testicles, and the extraction of teeth and nails. Also according to a former CIA analyst on Iran, Jesse J. Leaf, SAVAK was trained in torture techniques by the CIA. After the 1979 revolution, a CIA film was found which had been made for SAVAK security forces on how to torture women.
However, according to more recent research by a political historian of the era, Ervand Abrahamian, deaths numbered in the dozens rather than the thousands under the SAVAK, far fewer than the several thousand prisoners are estimated to have been killed in the Islamic Republic that followed. While some prisoners during the Shah's era were tortured, prisoners' letters were much more likely to use words such as "boredom" and "monotony," to describe their confinement than "fear," "death," "terror," "horror," and "nightmare" (kabos), the common descriptors found in letters of prisoners of the Islamic Republic.
SAVAK was closed down shortly before the end of the monarchy and the gain of power by Ayatollah Ruhollah Khomeini in the February 1979 Iranian Revolution. Following the departure of the Shah in January 1979, SAVAK's 3,000+ central staff and its agents were targeted for reprisals; almost all of them that were in Iran at the time of the Iranian Revolution were hunted down and executed, only a few who were on missions outside of Iran managed to survive. SAVAK has been replaced by the SAVAMA, Sazman-e Ettela'at va Amniat-e Melli-e Iran, later renamed the Ministry of Intelligence. The latter is also referred to as VEVAK, Vezarat-e Ettela'at va Amniat-e Keshvar, though Iranians and the Iranian press never employ this term, using instead the official Ministry title. The new organization is structurally identical to the old one and retains many of low- and mid-level intelligence personnel from the SAVAK. Many books have since been published about the pre-revolution status of Iran politicians, based on the documents found in SAVAK's offices.