Related Rule
South Africa
Practice Relating to Rule 89. Violence to Life
South Africa’s LOAC Manual (1996) provides that “wilful killing” is a grave breach of the 1949 Geneva Conventions. 
South Africa, Presentation on the South African Approach to International Humanitarian Law, Appendix A, Chapter 4: International Humanitarian Law (The Law of Armed Conflict), National Defence Force, 1996, § 40.
According to South Africa’s Revised Civic Education Manual (2004), “wilful killing … of any persons” is a grave breach of the law of armed conflict and a war crime. 
South Africa, Revised Civic Education Manual, South African National Defence Force, 2004, Chapter 4, § 57.
South Africa’s ICC Act (2002) reproduces the crimes listed in the 1998 ICC Statute, including genocide by “killing members of the group”, murder as a crime against humanity, as well as the war crimes of “wilful killing” of a person protected under the 1949 Geneva Conventions in international armed conflicts. The Act also reproduces war crimes listed in the 1998 ICC Statute regarding non-international armed conflicts, including “violence to life and person, in particular murder” of “persons taking no active part in the hostilities” and “the carrying out of executions without previous judgment pronounced by a regularly constituted court, affording all judicial guarantees which are generally recognised as indispensable”. 
South Africa, ICC Act, 2002, Schedule 1, Part 1, § (a), Part 2, § 1(a), and Part 3, §§ (a)(i), (c)(i) and (c)(iv).
In its judgment in the Basson II case in 2005, South Africa’s Constitutional Court stated:
There can be no doubt that the use of instruments of state to murder captives long after resistance had ceased would in the 1980s, as before and after, have grossly transgressed even the most minimal standards of international humanitarian law. 
South Africa, Constitutional Court, Basson II case¸ Judgment, 9 September 2005, § 179.
In its report on “gross violations of human rights” committed between 1960 and 1993, South Africa’s Truth and Reconciliation Commission stated:
Those combatants who were killed or seriously injured while they were unarmed or out of combat, executed after they had been captured, or wounded when they clearly could have been arrested were held to be victims of gross violations of human rights, and those responsible were held accountable. 
South Africa, Truth and Reconciliation Commission Report, 1998, Vol. 1, p. 76, § 102.