By 1960, he was the second man in the nationalist CONAKAT party, alongside Moise Tshombe. Munongo was interim president of Katanga Province from 26 April to 22 June 1961. Munongo was Minister of Interior for the Congo in 1965 and then led the eastern Katanga province until 24 April 1966, when the province merged with the neighbouring province of Lualaba. He was Governor of South Katanga until 5 November 1966. It has been claimed he was involved in ethnic cleansing of 1960 to 1962 in Katanga and tried to obtain Belgian support. It has been alleged that Munongo was involved in the death of Lumumba in 1961. Before his death Munongo was quoted in a newspaper as saying that he would, if Lumumba came to Katanga, do what the Belgians could not do and kill him. Lumumba and two other ministers were beaten on a plane journey to Katanga. Near the airport at Luano in Lubumbashi, they were all tortured, and Lumumba was personally assaulted by Katangan leaders, including Munongo and Belgian officers. After they were shot by a firing squad, their bodies were dissolved in acid. In reports Munongo said, "I will speak frankly, If people accuse us of killing Lumumba, I will reply: 'Prove it'." At the Conference Nationale Souveraine shortly before his death, Mabika Kalanda asked him, "Godefroid, you are one of the survivors who participated in the end of Patrice Émery Lumumba. Why would you not take advantage of the CNS to tell us your truth?" Munongo emotionally replied, "My dear Mabika, you put an important issue before me. What I can say at this stage is that I was not alone. We were numerous. We'll have to get all these people together. But anyway, I can say at that time, we were working, without realizing it, for the interests that were not ours. We were young". He died without ever fully recounting his role in Lumumba's death.
Later life
Munongo was recognised, by the Council of Notables, as the fifth Msiri, and he was enthroned on 12 September 1976. The family website records that Munongo was going to break his silence on the death of Lumumba, but on the day of the announcement, he suffered a heart attack and died on 28 May 1992. Munongo's son is involved in politics.
