Related Rule
Belgium
Practice Relating to Rule 89. Violence to Life
Belgium’s Law of War Manual (1983) prohibits, in internal armed conflicts, “attacks on the life and physical integrity” of “persons who do not take a direct part in hostilities, including members of the armed forces who have laid down their arms and persons placed hors de combat”. 
Belgium, Droit Pénal et Disciplinaire Militaire et Droit de la Guerre, Deuxième Partie, Droit de la Guerre, Ecole Royale Militaire, par J. Maes, Chargé de cours, Avocat-général près la Cour Militaire, D/1983/1187/029, 1983, pp. 16–17.
The manual further states that wilful killing is a grave breach of the 1949 Geneva Conventions. 
Belgium, Droit Pénal et Disciplinaire Militaire et Droit de la Guerre, Deuxième Partie, Droit de la Guerre, Ecole Royale Militaire, par J. Maes, Chargé de cours, Avocat-général près la Cour Militaire, D/1983/1187/029, 1983, p. 55.
Belgium’s Penal Code (1867), as amended in 2003, provides:
The crime of genocide, as defined below, whether committed in time of peace or in time of war, constitutes a crime under international law and shall be punished in accordance with the provisions of the present title. In accordance with the Convention for the Prevention and Punishment of the Crime of Genocide of 9 December 1948, and without prejudice to criminal provisions applicable to breaches committed out of negligence, the crime of genocide means any of the following acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group as such:
1. killing members of the group. 
Belgium, Penal Code, 1867, as amended on 5 August 2003, Chapter III, Title I bis, Article 136 bis, § 1.
The Penal Code further states:
A crime against humanity, as defined below, whether committed in time of peace or in time of war, constitutes a crime under international law and shall be punished in accordance with the provisions of the present title. In accordance with the Statute of the International Criminal Court, crime against humanity means any of the following acts when committed as part of a widespread or systematic attack directed against any civilian population, with knowledge of the attack:
1. … murder …
2. extermination. 
Belgium, Penal Code, 1867, as amended on 5 August 2003, Chapter III, Title I bis, Article 136 ter, §§ 1–2.
The Penal Code further provides:
War crimes envisaged in the 1949 [Geneva] Conventions … and in the [1977 Additional Protocols I and II] … , as well as in Article 8(2)(f) of the [1998 ICC Statute], and listed below, … constitute crimes under international law and shall be punished in accordance with the provisions of the present title … :
1. wilful killing. 
Belgium, Penal Code, 1867, as amended on 5 August 2003, Chapter III, Title I bis, Article 136 quater, § 1(1).
The Penal Code also states:
In the case of an armed conflict as defined in … Article 3 common [to the 1949 Geneva Conventions], the grave breaches of [common] Article 3, … listed below, shall constitute crimes under international law and shall be punished in accordance with the provisions of the present title, when such breaches endanger, by act or omission, persons protected by these Conventions, without prejudice to criminal provisions applicable to breaches committed out of negligence:
1. violence to life and person, in particular murder of all kinds. 
Belgium, Penal Code, 1867, as amended on 5 August 2003, Chapter III, Title I bis, Article 136 quater, § 2(1).
Belgium’s Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols (1993), as amended in 1999, provides that “wilful killing” constitutes a crime under international law. 
Belgium, Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols, 1993, as amended in 1999, Article 1(3)(1); see also Article 1(1)(1) (killing as a part of a genocide campaign) and Article 1(1)(2) (killing as a crime against humanity).
The Law also provides that, in accordance with the 1998 ICC Statute, extermination constitutes a crime against humanity and a crime under international law. 
Belgium, Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols, 1993, as amended in 1999, Article 1(2)(2).
Belgium’s Law relating to the Repression of Grave Breaches of International Humanitarian Law (1993), as amended in 2003, provides:
The crime of genocide, as defined below, whether committed in time of peace or in time of war, constitutes a crime under international law and shall be punished in accordance with the provisions of the present title. In accordance with the Convention for the Prevention and Punishment of the Crime of Genocide of 9 December 1948, and without prejudice to criminal provisions applicable to breaches committed out of negligence, the crime of genocide means any of the following acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group as such:
1. killing members of the group. 
Belgium, Law relating to the Repression of Grave Breaches of International Humanitarian Law, 1993, as amended on 23 April 2003, Article 1, § 1.
The Law further states:
A crime against humanity, as defined below, whether committed in time of peace or in time of war, constitutes a crime under international law and shall be punished in accordance with the provisions of the present title. In accordance with the Statute of the International Criminal Court, crime against humanity means any of the following acts when committed as part of a widespread or systematic attack directed against any civilian population, with knowledge of the attack:
1. … murder … [or]
2. extermination. 
Belgium, Law relating to the Repression of Grave Breaches of International Humanitarian Law, 1993, as amended on 23 April 2003, Article 1 bis, § 1–2.
The Law further provides:
War crimes envisaged in the 1949 [Geneva] Conventions … and in the [1977 Additional Protocols I and II] … , as well as in Article 8(2)(f) of the [1998 ICC Statute], and listed below, … constitute crimes under international law and shall be punished in accordance with the provisions of the present title … :
1. wilful killing. 
Belgium, Law relating to the Repression of Grave Breaches of International Humanitarian Law, 1993, as amended on 23 April 2003, Article 1 ter, § 1(1).
The Law also states:
In the case of an armed conflict as defined in … Article 3 common [to the (1949) Geneva Conventions], the grave breaches of [common] Article 3, … listed below, shall constitute crimes under international law and shall be punished in accordance with the provisions of the present title, when such breaches endanger, by act or omission, persons protected by these Conventions, without prejudice to criminal provisions applicable to breaches committed out of negligence:
1. violence to life and person, in particular murder of all kinds. 
Belgium, Law relating to the Repression of Grave Breaches of International Humanitarian Law, 1993, as amended on 23 April 2003, Article 1 ter, § 2(1).
In its judgment in the Sergeant W. case in 1966, Belgium’s Court-Martial of Brussels sentenced to imprisonment a sub-officer who wilfully killed a civilian while serving in the Congolese army within the framework of military technical cooperation between the Congo and Belgium. The Court held that the act committed was murder under the Belgian and Congolese Penal Codes and also a clear violation of the laws and customs of war and of the laws of humanity. 
Belgium, Court-Martial of Brussels, Sergeant W. case, Judgment, 18 May 1966.