05:32Heart and SoulDangerous MissionBBC World Service Duration: 27 minutes Sat 22nd May 2010, 05:32 on BBC World Service OnlineAvailable for over a yearListen nowAfter the killing of Christian aid worker Gayle Williams, we ask if missionaries are brave ambassadors or irresponsible.GenresReligion & EthicsFormatsDocumentariesBrandHeart and Soul Source: BBC Online