On 9 December 1976 he was appointed bishop of the Roman Catholic Diocese of Nyundo, and he was consecrated by Archbishop Vincent Nsengiyumva on 27 March 1977.

"[3] Perhaps because of Kalibushi's willingness to support Tutsis and his criticism of the government, his compound at Nyundo was one of the first targets of the Hutu extremists.

[4] The morning after the death of President Juvénal Habyarimana, on 7 April 1994 a number of Tutsi families came to Nyundo for safety.

A large, hostile and armed crowd arrived, and the killing began, including women and children who took refuge in the chapel.

Vincent Nsengiyumva wrote a letter to the Christians of Nyundo reassuring them that Kalibushi was safe and sound, and that rumors that he had fled to Nairobi were false.