ghost or demon?

I understand. We did not summon, we simply asked for whatever may already be there to show itself. We said "show yourself but do not cross" we did not use a name, and not really thinking anything would come, since we did not fully believe my dad was haunted by an entity. Well we knew he was plagued, but just did not know by a spirit. We were thinking more curse. But now we know. My family line, on his side, has all been cursed. This we all always knew. Well my dad thinks the spirit may be his grandpa, who was a murder suicide in PA in the 50's. Question now is, is he the source of the curse or a victim of it?