Hi Patrick,
Yes, I did find out that the story was true but Mary's husband, Henry Griffiths, was charged with manslaughter, not murder. I have the newspaper articles from the Merthyr Express, which Stephen Kings from Bargoed Library found for me.
I can email you copies of them if you would like to see them? I assume I can still contact you at the email address I have used before?
Regards
Trish