[1] An independent and multidisciplinary unit with a unique methodology which combined investigation, forensic intelligence, and prosecution, the Scorpions were known as an elite unit,[2][3] and were involved in several extremely high-profile investigations, especially into the Arms Deal and into high-ranking African National Congress (ANC) politicians including Jackie Selebi, Jacob Zuma, and Tony Yengeni.

President Thabo Mbeki announced the establishment of the Scorpions in June 1999, promising "a special and adequately staffed and equipped investigative unit... to deal with all national priority crime, including police corruption.

"[4] Though formally launched in Gugulethu on 1 September 1999 as the Directorate of Special Investigations,[5] the unit did not legally or operationally come into existence until January 2001, by which time it had been renamed DSO.

[2][3] It was formally disbanded in January 2009 and replaced by the Hawks, a move pushed through Parliament by the ANC and often alleged to have been politically motivated.

[6][7][8] The Scorpions were led by a Deputy Director of Public Prosecutions, a position first held by Frank Dutton (1999–2001) and later by Percy Sonn (2001–2003) and Leonard McCarthy (2003–2008).

[2] Though independent, as a unit of the National Prosecuting Authority (NPA) the Scorpions drew their budget through the Ministry of Justice and Constitutional Development and were ultimately subject to the Minister's oversight.

[9] The Scorpions gained a reputation for investigating and prosecuting high-profile cases, sometimes involving high-ranking politicians of the ruling party, the African National Congress (ANC).

The Scorpions led the multi-year investigation into the Arms Deal, which began in 2001[2] or earlier and which led to the conviction on fraud and corruption charges of ANC politician Tony Yengeni and businessman Schabir Shaik, a close associate of Deputy President Jacob Zuma, who was himself ultimately charged with corruption.

[18] He pled guilty in the Cape Town High Court to contravening the Regulation of Foreign Military Assistance Act of 1998.

[24] Selebi was ultimately convicted, following a highly politicised trial – in the run-up to which the chief prosecutor, Gerrie Nel of the Scorpions, was himself arrested, and the head of the NPA, Vusi Pikoli, suspended.

Common complaints were that the details of the Scorpions' investigations were frequently leaked to the public before prosecution had commenced; that the Scorpions abused their power in exercising search and seizure warrants (including in the Zuma investigation, in which the ANC said that they had displayed "Hollywood tactics");[30] that they pursued selective and politically motivated prosecutions; and that they did not work well with the South African Police Service (SAPS).

[9] Zuma won the election comfortably, and the conference resolved that the Scorpions should be disbanded "as a matter of urgency" in order to facilitate the constitutional imperative of a "single police service.

In May 2008, while the relevant legislation was before Parliament, the Pretoria High Court heard an application to interdict, on constitutional grounds, the disbanding of the Scorpions.

Dissenting judges said that the Hawks did have structural and operational autonomy, while the majority judgement, prepared by Dikgang Moseneke and Edwin Cameron, found otherwise.