Wikipedia
"Lamkin" or "Lambkin" ( Roud 6, Child 93) is an English-language ballad. It gives an account of the murder of a woman and her infant son by a man, in some versions, a disgruntled mason, in others, a devil, bogeyman or a motiveless villain. Versions of the ballad are found in Scotland, England and the US.
According to Roud and Bishop
"Lambkin" is not one of the major league Child ballads in terms of popularity, but it was widely known in England and Scotland, and even more so in North America. ... . The central character's name varies considerably, including, in just the English versions 'Lambkin', 'Lamkin', Lincoln' and 'Limkin", and he is various referred to as 'Long', 'Bold', 'Cruel' and 'False'.
They cite the analysis of Ann Gilchrist, who identified two threads: one Scottish, which retained the mason narrative; one Northumbrian, which lost the mason in early versions, thus encouraging singers to supply a different back-story. Versions collected in England stem from the Northumbrian thread.