Benjamin

Benjamin, son of Mosiah(1), was selected by Amaleki to become the custodian of the Nephite records:

Benjamin was a righteous Nephite king and prophet in the Book of Mormon. He was the son of King Mosiah(1) [Mosiah 1:2]. King Benjamin taught his sons, including Mosiah, the language and prophecies of their fathers, and the importance of the records engraved on the plates of brass and the plates of Nephi [Mosiah 1:2-7].

When King Benjamin became old, he conferred the kingdom upon his son Mosiah and gave him charge over the records, including the plates of brass and the plates of Nephi, as well as the sword of Laban and the ball or director that led their fathers through the wilderness [Mosiah 1:15-16].

Mosiah was then chosen as king and was given custody of the records and other important items [Mosiah 1:10]. This suggests that Amaleki, the last writer in the book of Omni, selected Mosiah, the son of King Benjamin, to become the custodian of the Nephite records [Omni 1:25].

Learn more:

1. Mosiah 1
2. Mosiah, Son of Benjamin
3. Book of Mormon, 1830, Page 168