Amulek had an ancestor named Aminadi, a descendant of Nephi, "who interpreted writing which was upon the wall of the temple, which was written by the finger of God" (Alma 10:2). Who was this man and when did this happen? According to Verneil Simmons, the only mention of this dramatic story is the above reference.
In the Bible account of a similar story told in the book of Daniel (Daniel 5), the finger of the Lord writing on the wall of the palace spelled doom and destruction to the king of Babylon and his kingdom. Did the Lord warn the Nephites at the temple in the City of Nephi by a similar method, that destruction was imminent? When Mormon wrote the words of Amulek he apparently felt no further need to explain them. [Verneil W. Simmons, Peoples, Places And Prophecies, p. 161]
Note* The reader should note that there is a connection between the sudden destruction of the kingdom of Babylon as forseen in Daniel 5, and the prophecies of Alma and Amulek concerning the sudden destruction of the city of Ammonihah. (Alma 10:20-27; 16:1-11). [Alan C. Miner, Personal Notes]