Sergio (2009)

Charismatic, charming and complex, Sérgio Vieira de Mello was the world's go-to guy, a man who could descend into the most dangerous places, charm the worst war criminals, and somehow protect the lives of the ordinary people to whom he'd devoted his life. The documentary tells the story of his most treacherous mission ever... a mission in which his own life hangs in the balance.

Source: TMDb