In November 2010, Macdonald led a CBC investigation into the United Nations International Independent Investigation Commission and the Special Tribunal for Lebanon, which had been mandated with solving the murder of former Lebanese Prime Minister Rafik Hariri. The report uncovered documents suggesting the UN investigative body had strong evidence to link the Shia paramilitary group Hezbollah to the 2005 bombing that killed Hariri, and that the UN had not acted on this intelligence due to diplomatic concerns. Macdonald's report also sharply criticized the performance of the Special Tribunal's head prosecutor, Daniel Bellemare, who responded that he was "extremely disappointed" with the report.