Readers of this thread may care to have a look at a recent article by Tom Pettit on the Musical Traditions website. The article is "The Mary Thompson Cluster" (MT Article 319)and shows how a number of supposedly true accounts of various murders are actually all based on one story, which, it seems, is not true! In one case, the girl is actually murdered twice by two different men. Just the sort of thing that can happen in folksongs, I guess.