I obtained this quest from Alan Binet. When I went to Group Manor (which I already cleared and built a Settlement at) I just saw my settlers there which is what you would expect. I was wondering why the quest was sending me to a a place I had already cleared and built a Settlement at but thought it might had spawned Feral Ghouls around the area for me to kill. Nope, there was no Feral Ghouls anywhere around or in Group Manor. I am unable to complete this quest. Has anyone ran into this issue and found a way to compete it?

i did run into the issue, unfortunately i can't seem to recall how i solved it in the end, due to the endless number of futile tries that came before that.

i remember resurrecting and re-killing a lot of ghouls though, and dragging a lot of bodies to the area from elsewhere to try the same...

also remember having given up on it for a while and gone somewhere else, maybe returning later fixed it...

darn.. should i recall, i'll post

edit: ah yes, and did you check the basemant?