Tim Jacques - I class the false knight/ false lover John song as a murder ballad because He was going to murder Polly.

John Lewis treated " 'Omie Wise" in a similar fashion

I see mention of "There was an old woman who lived in the wood, weela weela waile..." (infanticide song)in the "Dark Irish Kids" thread, but I don't feel like typing out the words just now, even though I know them. The adult versions are best known as "Down by the Greenwood Side" or "The Cruel Mother" (the latter title appears in the DT).