Mbahou, an ethnic Bembe and native of Bouenza who held the rank of colonel, was Lissouba's Director of Presidential Security from 1992 to 1997. In October 1997, when Lissouba was ousted by rebels loyal to Denis Sassou Nguesso at the conclusion of a civil war, Mbahou fled into exile. While in exile, he remained sympathetic to the opposition to Sassou Nguesso and met with the opposition leader Emmanuel Ngouélondélé.