My understanding of pre-Columbian history is there was a period where warlike tribes in the less forgiving North raided and drove the southern tribes further south. Essentially descendants of the true “first” Americans are down in Chile and Argentina.
How the tribes treated each other before the White Man arrived. My short list.
http://wkfl.asn.au/bk/crow_creek_history.htm
https://ournativeamericans.blogspot.com/2018/07/1300s-crow-creek-massacre-in-south.html
https://www.sciencenews.org/article/massacre-sacred-ridge
https://bonesdontlie.wordpress.com/2012/04/03/basketmaker-ii-cave-7-massacre-or-cemetery/
https://mcclungmuseum.utk.edu/1991/12/01/scalping-victim/
https://prezi.com/z9ioohxrdgat/anasazi-cannibalism/?fallback=1
https://www.nbcnews.com/id/wbna39268873
https://www.historynet.com/when-the-sioux-ambushed-pawnee-hunters-at-massacre-canyon/
http://www.dickshovel.com/scalp.html
https://lostworlds.org/ancient-massacre-discovered-in-new-mexico-was-it-genocide/
https://www.archaeology.org/news/2269-140630-colorado-torture-evidence
https://lostworlds.org/ancient-massacre-discovered-in-new-mexico-was-it-genocide/
https://www.ancient-origins.net/news-history-archaeology/sacrifice-victims-cahokia-were-locals-not-foreign-captives-003685
https://www.jstor.org/stable/1593823
https://archive.archaeology.org/9709/newsbriefs/anasazi.html
https://www.cbsnews.com/news/mexico-skulls-not-crime-scene-human-sacrifice-ad-900/
https://www.cbsnews.com/news/mexican-site-reveals-brutal-sacrifice-of-spanish-conquistadors/
https://www.okhistory.org/publications/enc/entry.php?entry=SL002
http://blogoklahoma.us/place/117/kiowa/cutthroat-gap-massacre
https://www.okhistory.org/publications/enc/entry?entry=CU012
https://www.okhistory.org/publications/enc/entry?entry=CL003