Helaman 3:16

and they have been handed down from one generation to another, by the Nephites, even until they have fallen into transgression, and have been murdered, plundered, and hunted, and driven forth, and slain, and scattered upon the face of the earth, and mixed with the Lamanites until they are no more called the Nephites, becoming wicked, and wild, and ferocious, yea, even becoming Lamanites.

The Nephites have passed them down from one family to the next. They did this until they sinned. Then they were murdered, robbed, hunted, driven away, killed, and scattered across the earth. They mixed with the Lamanites. They were not called Nephites anymore. They became evil, wild, and mean. They became Lamanites.

They passed these records down from one generation to the next—until the Nephites fell into sin and were murdered, plundered, hunted, driven out, killed, and scattered across the earth. They mixed with the Lamanites until they were no longer called Nephites. They became wicked, wild, and violent—indistinguishable from Lamanites.