In 1965, Prime Minister Milton Obote and Amin were implicated in a deal to smuggle ivory and gold into Uganda from the Democratic Republic of the Congo. The deal, as later alleged by General Nicholas Olenga, an associate of the former Congolese leader Patrice Lumumba, was part of an arrangement to help troops opposed to the Congolese government trade ivory and gold for arms supplies secretly smuggled to them by Amin. In 1966, the Ugandan Parliament demanded an investigation. Obote imposed a new constitution abolishing the ceremonial presidency held by Kabaka (King) Mutesa II of Buganda, and declared himself executive president. He promoted Amin to colonel and army commander. Amin led an attack on the Kabaka's palace and forced Mutesa into exile to the United Kingdom, where he remained until his death in 1969.