After the overthrow of Milošević, Đukanović faced a dilemma as he no longer could use Milošević's international standing to argue for Montenegro's independence from Yugoslavia. In early 2002, Đukanović was subject to an investigation on international cigarette trafficking by the public prosecutor Giuseppe Scelsi of Bari. Simultaneously, he was involved in negotiations ahead of the Belgrade agreement, and Javier Solana tried persuading him to abstain from independence at least temporarily and that Montenegro should remain in Yugoslavia. After the meetings with Solana, Đukanović signed the Belgrade Agreement on 14 March 2002, in addition to the signatures of Filip Vujanović, Zoran Đinđić, Vojislav Koštunica, and Miroljub Labus. The agreement led to the Constitutional Charter of Serbia and Montenegro. It mandated that after a period of three years, Montenegro could hold a referendum on the question of independence. In a bid to prolong his executive powers, Đukanović and Prime Minister Vujanović agreed a job-swap that same year. Đukanović did not run for president in the 2002 election and Vujanović replaced him as the DPS candidate. On 25 November 2002, Đukanović resigned as president, several months before the end of his term, in order to become Prime Minister again. Vujanović, who had resigned as prime minister at the start of the month to become Speaker of the Montenegrin Parliament, was sworn in as acting president. Đukanović took office as prime minister on 8 January 2003. Vujanović succeeded him as president on 22 May 2003.