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.

[15][clarification needed] After 1963, the Shah expanded his security organizations, including SAVAK, which grew to over 5,300 full-time agents and a large but unknown number of part-time informers.

Pakravan was replaced in 1966 by General Nematollah Nassiri, a close associate of the Shah, and the service was reorganized and became increasingly active in the face of rising leftist and Islamist militancy and political unrest.

[18][19] According to Iranian political historian Ervand Abrahamian, after this attack SAVAK interrogators were sent abroad for "scientific training to prevent unwanted deaths from 'brute force.'"

Brute force was supplemented with the bastinado; sleep deprivation; extensive solitary confinement; glaring searchlights; standing in one place for hours on end; nail extractions; snakes (favored for use with women); electrical shocks with cattle prods, often into the rectum; cigarette burns; sitting on hot grills; acid dripped into nostrils; near-drownings; mock executions; and an electric chair with a large metal mask to muffle screams while amplifying them for the victim.

[22] 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.

The agency also closely collaborated with the CIA by sending their agents to an air force base in New York to share and discuss interrogation tactics.

[34][35] Two days before the Saur Revolution in 1978, the KGB were informed of the coup by Afghan Army leaders Mohammed Rafie and Sayed Mohammad Gulabzoy.

As a result, the KGB mistakenly informed its operatives in Kabul that SAVAK tricked the PDPA into starting a rebellion, expecting it to be crushed and for the rebels to fail.

[36] According to Polish author Ryszard Kapuściński, SAVAK was responsible for: Censorship of press, books, and films; Interrogation and often torture of prisoners; and Surveillance of political opponents.

The FAS list of SAVAK 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".

[41] According to author Charles Kurzman, SAVAK was never dismantled but rather changed its name and leadership and continued on with the same codes of operation, and a relatively unchanged "staff.