Operating in the late 1970s along the Sunset Strip corridor of Los Angeles, Clark carried out a series of murders in partnership with Carol Mary Bundy, targeting vulnerable women and young girls. The case drew particular attention for the nature of the crimes and the dynamic between the two accomplices, whose collaboration enabled a pattern of violence that investigators linked to at least seven deaths.

Operating across a roughly year-long period in the mid-1990s, Thwala exploited the economic desperation of local women in KwaZulu-Natal, using false promises of employment to draw victims into remote sugarcane fields. His method of disposal — relying on routine agricultural burning to destroy evidence — allowed the killings to continue and complicated the police investigation until a preserved crime scene finally broke the case. The eventual breakthrough came through DNA evidence, linking him to prior criminal contact with law enforcement, and resulted in convictions for 16 murders and 10 rapes.

The organization he built became the principal vehicle for transnational jihadist violence in the late twentieth and early twenty-first centuries, responsible for coordinated attacks across multiple continents and culminating in the September 11, 2001 strikes that killed nearly three thousand people in the United States. His effectiveness lay partly in his ability to recruit, finance, and network across borders — skills developed during the Soviet-Afghan War — and partly in a ideological framework that framed violence as religious duty on a global scale.