I am thinking that there was some information on this in Kirby Ross' Hildebrand book, but I cannot recall and don't have the book at hand.
Local folks have many stories about the killings, but most are improbable. Seems like there were perhaps more killed than buried at the cemetery but the others were not from the area. People apparently went and got the bodies and brought them back to the Cowan Cemetery. I'll try to find some sources.