A pharmacist by profession, Piliso joined the ANC's external mission in 1960 and represented it abroad in Cairo and Dar es Salaam for the next decade.
His tenure at NAT over the next five years coincided with serious abuses by the department's internal security wing, known as Mbokodo, which tortured and even executed suspected spies and brutally suppressed a mutiny by MK recruits.
[2][3] In early 1981, Tambo appointed Piliso as director of the ANC's National Intelligence and Security Department (NAT), which at the time was highly preoccupied with concerns about ill-discipline and spying in MK camps.
[3][5] The security wing, nicknamed Mbokodo (Xhosa for "the grinding stone"), became notorious among the MK rank-and-file for its abuses, particularly in the camps' detention centres.
[5] Over the next two years, NAT's governance structures were reformed and then suspended, until in 1987 the entire directorate was dissolved and replaced, and Piliso was transferred to become head of the ANC's Manpower Development Department.
[1] The return of MK recruits to South Africa was accompanied by media attention to their experiences in exile, and the ANC established two separate internal commissions of inquiry to investigate complaints in 1992–1993.
[12] He received substantial media attention as a result, with the Weekly Mail's front page declaring him the "ANC's torture chief".
[13] The commission specifically asked the ANC how it "justifies the fact that Mzwai Piliso and [MK commissar] Andrew Masondo retained senior posts in the post-1994 administration".
In addition, these officials had not acted with personal vindictiveness; they had acted within the broader context of weaknesses and problems afflicting the ANC as a whole...[5]During the hearings, Piliso was linked to specific abuses – specifically to the death of Joe Seremane's brother, Timothy, a suspected spy[14] – and more broadly was, with Masondo, "widely... held responsible for letting conditions in Angolan camps get out of control".
[2] He developed diabetes upon his return to South Africa and died of related illness on 25 June 1996 at St Dominic's Hospital in East London.