United Nations has rejected Pakistan's appeal to reopen the probe into the assassination of former premier Benazir Bhutto. UN Secretary General Ban Ki-moon has said that the investigation into th assassination is complete.Last week, Islamabad had raised objections to the report that was presented by a UN appointed three-panel fact finding commission in April. <br/><br/>54-year-old Bhutto was killed on December 27, 2007 when a suicide bomber exploded himself close to her car in Rawalpindi while she was campaigning for the Pakistan People's Party (PPP) in parliamentary and provincial elections.<br/><br/>The inquiry commission which was set up in 2009 to ascertain the facts and circumstances of Bhutto's death, concluded that the assassination could have been prevented.