Right, Willie McTell recorded the only verse that gives a reason for his actions:

Deliah, oh Deliah, How could it be?
You loved all those rounders, but you never really did love me,
Deliah's gone...

Johnny's only remorsful verse is:

First time I shot her, I shot her in the side.
Couldn't watch her suffer, but with the second shot she died,
Deliah's gone...

I think the first version I ever heard was by Burl Ives in the late fifties or early sixties.