Ouvéa was declared a military zone and all communication and transport was cut. More than 300 soldiers were flown to the island and Captain Philippe Legorjus, head of France's elite antiterrorist squad, began negotiations with the hostage takers. During attempts to secure the hostages' release, Legorjus was captured but was freed after coming to an agreement with the group's young leader, Alphonse Dianou, on a date of release for the hostages. It was set for after the presidential election.
On 4 May, three days before the election, Captain Legorjus had two guns and a set of handcuff keys smuggled into the cave. In what was code-named Opération Victor, the military then stormed the cave and reported 'at least 16' people dead, all of them Kanaks. The following day, the figure was revised to 21, including two gendarmes. Later, allegations were made that four of the Kanaks, including the leader, Dianou, and Waine Amossa, a 19-year-old who had been sent into the cave to deliver food, were killed after they had surrendered. It was also claimed that the military tortured and beat civilians from Goosana during the operation. The human rights group Amnesty International took up the case, and France's Minister for Defence later announced that 'acts contrary to military duty have unfortunately been committed'. One gendarme was suspended but no judicial action was taken.
After the cave assault, 32 Ouvéan prisoners, including Djubelly Wea, a local independence movement leader and FULK (Front Uni de Libération Kanak) supporter, were flown to France to face trial. This was despite a previous assurance from the French High Commissioner in New Caledonia that trials would be held in Noumea. Wea was eventually released and the others were given amnesty as part of the Accords de Matignon. Wea returned home to find that his elderly father had died shortly after the hostage crisis. His father had apparently been beater and left tied up in the sun by the military, and was soon regarded as the '20th victim' of the Ouvéa massacre."