Internal Security Department (Singapore)

The Internal Security Department or ISD is the domestic intelligence, counter-espionage and security agency of Singapore under the purview of the Ministry of Home Affairs (MHA). It is tasked to confront and address security threats ranging from subversion or sedition, spying or espionage, foreign influence, domestic or international terrorism, political or religious extremism, and fraud against the state.

Deputy Prime Minister Goh Keng Swee stated that 'an efficient secret police' was necessary to counter dangers such as insurgencies and violent rebellions. The ISD is empowered to conduct mass surveillance and covert security operations; it has the utmost right to indefinitely detain without trial individuals suspected to be a threat to national security.

Although the agency falls under MHA, it is autonomous within the ministry. It is led by a director, who holds the rank equivalent to a permanent secretary, and reports directly to the Prime Minister's Office (PMO). The department is highly secretive; most of its personnel are only known to the country's top government officials.

History
The department was initially established as the Criminal Intelligence Department in 1918 after the Sepoy Mutiny of 1915. In 1933, the CID was renamed as Special Branch.

In 1939, it was restructured into the Malayan Security Service (MSS) which was not yet fully operational by the time of the outbreak of the Second World War. The MSS was disrupted by the Japanese invasion and subsequent occupation of Singapore and Malaya. It was disbanded in 1948 and two secret branches, one in Singapore and the other in Malaysia, were created.

The Singapore Special Branch (SSB) was first established on 23 August 1948 by the British colonial government, after the Communist Party of Malaya (CPM) launched an armed uprising to establish a communist state. It was structured under the Singapore Police Force and headed by a Deputy Commissioner.

After Singapore achieved independence, the SSB was renamed as the Internal Security Department and became a separate agency on 17 February 1966, together with its foreign counterpart, the Security and Intelligence Division (SID). Both agencies operated under the former Ministry of Interior and Defence until 11 August 1970, when the ministry was split into the Ministry of Defence (MINDEF) and MHA with SID and ISD falling under the them respectively.

Communist Threat
During the Malayan Emergency between 1948 to 1960, the CPM attempted to overthrow the government to win independence for Malaya from the British Empire and to establish a socialist economy. During the 12-year conflict, the CPM raided British colonial police and military installations. It also attempted to bankrupt the British occupation by raiding economic targets such as mines, plantations, and trains. The Singapore SB worked in cooperation with its British and Malayan counterparts to stop the Communist threat by destroying armed cells and rooting out CPM agents embedded within various civil organisations such as trade unions.

A covert security operation in 1963, known as Operation Coldstore led to the detention of 113 suspected subversives.

1960 CIA Plot
From 1960 to 1961, the Central Intelligence Agency (CIA) attempted to recruit Yoong Siew Wah, an inspector in SSB, as a mole to provide them with sensitive security intelligence. Prime Minister Lee Kuan Yew authorised a double agent operation with Wah playing along with the CIA. While meeting CIA officers in a safe house, SSB agents, which had been earlier deployed around the house, moved in to make arrests.

Two polygraphers managed to escape in a car leading to a car chase which ended in their arrest and the seizure of a polygraph machine. A CIA officer working under the cover of an embassy First Secretary was declared persona-non-grata and expelled from Singapore. Lee was personally offered with US$3.3 million to him and his political party, People's Action Party, to cover up the matter but he rejected it and demanded US$33 million in economic aid instead. Dean Rusk, then U.S. Secretary of State, formally acknowledged the affair and apologised in a letter.

In 1965, during a televised interview with foreign correspondents about the British bases in Singapore, Lee revealed the CIA plot. After the broadcast, James D. Bell, U.S. ambassador to Malaysia, and the State Department denied the incident, leading a furious Lee to display the letter from Rusk to correspondents. Lee also threatened to broadcast tape recordings proving the charge. The denials were withdrawn with a closed congressional record suggesting that the State Department and the ambassador were both unaware of the case as new officials had failed to consult the files.

Jemaah Islamiyah operations in Singapore
In the late 1980s, Jemaah Islamiyah created a Singapore branch with Haji Ibrahim bin Haji Maidin as the leader of the Singapore branch. Ibrahim recruited members through religious classes which he conducted at private residences. The Singapore branch had an estimated 60 to 80 members in a 2002 estimate by the ISD.

JI aimed to establish a dawlah islāmiyyah (Islamic state) in Southeast Asia and planned a series of attacks to occur in the aftermath of the September 11 attacks against the United States. Close to 80 targets were identified with plans to bomb a shuttle bus ferrying American military personnel and their families from Sembawang to Yishun MRT station. Other targets included key military installations like the MINDEF Headquarters at Bukit Gombak, U.S. and Israeli Embassies, British and Australian High Commissions, the Singapore American School, and commercial buildings housing US firms.

Primarily, JI scheduled major coordinated attacks against the American and Israeli embassies; the Australian and British high commissions, the Singapore American School, Sembawang Wharf and Changi Naval Base, as well as commercial buildings hosting American multinational companies. The plotters had made arrangements to procure 17 tonnes of ammonium nitrate, 6 tonnes of trinitrotoluene (TNT), 300 pieces of detonators, 2.4 km of detonator cord, and six trucks (to be filled with the explosives).

In 2001, Ibrahim was arrested by ISD. ISD was then informed that another Singaporean, Mohammad Aslam Yar Ali Khan, had links to Al-Qaeda. In December, the ISD arrested 15 people under the Internal Security Act for terrorism-related activities. 13 of the arrested people were determined to be JI members and were served with Orders of Detention. The other two non-JI members were released on Restriction Orders. Aslam would later be arrested by the Northern Alliance in Afghanistan.

In 2002, a review of the cases 13 detainees was done by an independent advisory board. The subsequent report by the board supported the ISD’s detention of the JI members. In august, ISD arrested 21 Singaporeans which consisted of 19 JI members and 2 Moro Islamic Liberation Front members. Out of the 21, 18 were detained while the remaining three were released on Restriction Orders.

In 2023, during the ISD's 75th Anniversary Gala Dinner, Prime Minister Lee Hsien Loong, in his speech, pointed out one of ISD's first female Operations officers, "Tiger Lily", who was instrumental in breaking into the Singapore JI network. She had managed to get close to the JI Muslimah, wives of JI members, and subsequently through them to persuade their husbands to reveal their JI involvement and cooperate with ISD investigations.

Joint Counter Terrorism Centre
In 2004, the Joint Counter-Terrorism Centre (JCTC) was setup under the National Security Coordination Secretariat (NSCS) of the Prime Minister's Office (PMO) to deal with security threats and terrorism. This meant that the SID and the ISD, which previously worked independent of each other, had to share information for the first time.

Legislation
The powers of investigation and arrest of the ISD are regulated by several laws, including:
 * Internal Security Act
 * Official Secrets Act
 * Criminal Procedure Code
 * Maintenance of Religious Harmony Act
 * Foreign Interference (Countermeasures) Act

Directors
The following is a list of former directors of the Internal Security Department. The identity of the director is not conspicuously made known to the public, until they relinquish the post.