I don't think she is a descendant of the Black Donnelly's.
From Wikipedia, The "Black" Donnellys were an Irish family who emigrated to Ontario. Five of the family were murdered by an armed mob in the township of Lucan Biddulph in February 1880 and their farm was burned down, the culmination of long-standing conflict between the family and other residents. No one was convicted of the murders, despite two trials.
Here is the profile for the patriarch, James Donnelly.