In October 1990, Rwigema led a force of over 4,000 RPF rebels into Rwanda at the Kagitumba border post, advancing south to the town of Gabiro. Kagame was not present at the initial raids, as he was in the United States, attending the Command and General Staff College in Fort Leavenworth, Kansas. On the second day of the attack, Rwigema was shot in the head and killed. The exact circumstances are disputed; the official line of Kagame's government, and the version mentioned by historian Gérard Prunier in his 1995 book on the subject, was that Rwigyema was killed by a stray bullet. In his 2009 book "Africa's World War", Prunier says Rwigyema was killed by his subcommander Peter Bayingana, following an argument over tactics. According to this account, Bayingana and fellow subcommander Chris Bunyenyezi were then executed on the orders of Museveni. In a 2005 conversation with Caplan, Prunier provided a different account, stating that Bayingana and Bunyenyezi's killers were recruited by Kagame. Caplan notes that lack of research means the truth of this is uncertain, but that if true, the "tales of death and intrigue yet another insight into Kagame's character". Rwigyema's death threw the RPF into confusion. France and Zaire deployed forces in support of the Rwandan army, and by the end of October, the RPF had been pushed back into the far north east corner of the country.