Hi
Welcome to Rootschat
If you follow this link to the
Gresham Hotel shootings it gives you an idea of what went on.
I have added your grandfather's name there, and a link to a page on him(nothing there on his page except your remarks at the moment) If you would like to post more info about your grandfather and what you know of the Gresham shootings I would be happy to add it
You will find it difficult to get confirmation outside of the family, as the leader was Paddy Moran, of that group, and he was hanged for another of the shootings that morning - but is is accepted that he did in fact lead the Gresham hotel group
Did your grandfather make one of those historical statements?