There is a lot of good information on the web for "Tom Dooley" that a simple search will turn up, so I won't go into much detail on that. But the song is based on an actual event, which always makes a tune more interesting to me. How much is fact and how much is fiction is always debatable, but something in that mix must resonate, given "Tom Dooley"s resonance through the decades.
I always noticed the unique POV - the verses are first person, the choruses second person. Can you think of any other songs that do this? And it's not like different people sing the two parts in any version I've been part of or heard.
The last verse's lines about "down in some lonesome valley, hanging from a white oak tree" calls to mind Judas Iscariot, intentionally, I presume.
In Wilkes, NC, where the murder took place, has a Tom Dooley Museum and an annual play about the love triangle. Here is a link to the theatre:
Tom Dooley's last words: "“Gentlemen, do you see this hand? I never harmed a hair on Laura Foster’s head”