President Habyarimana was killed when his plane was shot down on the evening of April 6.23 Within hours members of the armed forces had killed political leaders opposed to Hutu Power, thus fulfilling the prediction made by the head of military intelligence in July 1992. Among the first killed was the prime minister, Agathe Uwilingiyimana. These slain politicians were seen as responsible for concessions to the RPF and several of them, including Madame Uwilingiyimana, were also seen as obstacles to installing a new political configuration, comprised only of Hutu Power supporters. After these leaders from the previous government were eliminated on April 7, military and political leaders of Hutu Power designated and installed a new government to implement its objectives.
Soon after members of the armed forces, reservists, Interahamwe and other militia, and ordinary civilians began hunting down and killing Tutsi. At sites where Tutsi had gathered in the thousands and put up resistance, soldiers and national police officers led the attacks, sometimes even using such weapons as mortars. The militia under political party leadership, and ordinary civilians organized by the local administrative officials, followed up the initial assaults, using a few firearms and many traditional weapons.
The soldiers and national police officers guarded the most important barriers and patrolled the main roads while the Interahamwe militia and the ordinary civilians guarded barriers at less crucial points, such as on local roads, and carried out footpatrols in neighborhoods.
The preparations for civilian self-defense had not been finished when the unexpected assassination of President Habyarimana triggered its implementation, but the basic lines were clear enough to make the process work: military and administrative officials cooperated, members of the armed forces providing the military know-how and the administrators supplying the manpower, recruited according to administrative unit of residence.
With a Hutu Power government in power after April 9, 1994, those who had secretly elaborated a self-defense plan could now make it formal and public. Ten days after the government took office, the authorities directed recruitment for civilian self-defense in the southern prefecture of Butare and elsewhere. The local military commander cooperated with administrative officials, the burgomasters and communal councilors to recruit young men who were to be selected according to the administrative unit in which they lived, to remain resident at home, and to be trained in the use of arms by communal police officers or reservists.24
The new prime minister, Jean Kambanda, and the minister of interior further formalized the self-defense program in decrees signed on May 25, 1994. According to former Prime Minister Kambanda, several ministers referred frequently to the document on Organisation de lAuto-Défense Civile, in the course of cabinet discussions about the program.25 This assertion is borne out by a comparison of the late May decrees with the document from February or March 1994. The same objectives are listed for the program, and some of the same phrases are used to describe positions and responsibilities in the system. As with the earlier plan, the ministers of interior and defense were to head the system, but in the later version, the minister of interior is the chair and the minister of defense the vice-chair, instead of the two being of equal importance.26
With the formal establishment of the system, the Interahamwe became incorporated into it, their highly trained groups serving as the elite units to lead the less well trained or untrained ordinary civilians. According to Kambanda, the militarily trained Interahamwe were systematically incorporated into the civil defense under the label youth of republican tendencies (a phrase much like that found in the Organisation de lAuto-Défense Civile document), thus in effect giving clear government approval to the crimes in which they had been engaged since early April.27
In the weeks before its formal establishment, as in the weeks after, the civilian self-defense system was used to mobilize ordinary civilians to hunt Tutsi civilians who had been identified with the military enemy. Using the civilian self-defense effort against non-combatants, military, administrative and political authorities transformed the system from a potentially legitimate form of self-defense into a violation of international law; by defining the group to be targeted as Tutsi and seeking their elimination, the authorities transformed the self-defense system into a weapon for genocide.
 Although those responsible have not been definitively identified, the long-awaited results of a French judicial inquiry into the shooting down of the airplane are said to attribute the crime to the RPF, a position held also by several former RPF soldiers now in exile.
 Lt. Col. Tharcisse Muvunyi, Comd. Place BUT-GIK to Monsieur le Bourgmestre, no. 0085/MSC.1.1, April 21, 1994.
 Jean Kambanda, Elements de Defense de Jean Kambanda, January 28, 2000, p. 28.
 Jean Kambanda, Premier Ministre to Monsieur le Préfet (Tous), Directive du Premier Ministre aux Prefets pour lOrganisation de lAuto-Défense Civile, no. 024/02.3, May 25, 1994 and Edouard Karemera, Ministre de lIntérieur et du Développement Communal, to Monsieur le Préfet (Tous), May 25, 1994.
 Jean Kambanda, Les Circonstances entourant mon arrestation le 18 juillet 1997 à Nairobi au Kenya, ma detention en Tanzanie, mon transfert aux Pays-Bas et mon procès en appel, a document with 25 annexes, dated October 19, 1999.