The Amulonites were the descendants of Amulon and his associate wicked priests of King Noah. They were Nephites on their father’s side, and Lamanites on their mother’s, but by association and education, were of the latter race.
Many of them, however, were displeased with the conduct of their fathers and took upon themselves the name of Nephites, and were considered among that people ever after. Of those who remained Amulonites, many became followers of Nehor and were scattered in the Lands of Amulon, Helam, and Jerusalem, all of which appear to have been districts in the same region of country. It is recorded of them that not one repented and received the Gospel Message that was preached by the sons of King Mosiah; on the contrary, they became leaders in the persecution carried on against the suffering people of Anti-Nephi-Lehi.
(George Reynolds and Janne M. Sjodahl, Commentary on the Book of Mormon, 3:290)