There is lack of clarity about the course followed by the Lamanites from the land of Noah (see the preceding commentary on Alma 16:3). Holding prisoners from the Noah area (Alma 16:3), the Lamanites apparently followed a route that took them to a "south wilderness" at a point near the extreme upper Sidon "away up beyond the borders of Manti" (Alma 16:6). Nevertheless the Nephites became aware of their course through Alma's seership. Thus the Nephites probably moved along a more known and less lengthy trail in order to intercept them. Apparently gaining ground on the Lamanites in this way, the Nephites got into advance position above Manti at a crossing point on the upper river (Alma 16:7). There are a few questions we might ask here: First, what was the purpose of taking prisoners in the first place? Second, why did it take the Lamanites so much time in their travels that the problem of their whereabouts was able to be communicated to Alma (apparently residing in the capital city of Zarahemla) and then communicated back to the Nephite army, thus allowing the Nephite army to beat the Lamanites to the "south wilderness" (Alma 16:4-8)? Third, where was the "east wilderness" mentioned in Alma 25:5 and 25:8? Fourth, after being headed by a Nephite army, why did the Lamanites scatter into an "east wilderness" when they were so close to the land of Nephi and their homelands on the south of the head of the Sidon, which was in the narrow strip of wilderness which separated the land of Nephi from the land of Zarahemla (Alma 22:27)? [Alan C. Miner, Personal Notes] [See Geographical Theory Maps]
“They Had Taken Others Captive into the Wilderness”
According to Brant Gardner, Mesoamerican warfare was extremely prevalent, and had many causes, only some of which were the addition of tributary cities. In this attack on the city of Ammonihah, there is no particular attempt at creating a tributary city, but rather this is a war of annihilation. It is not a complete annihilation, however, as there are captives taken back with the Lamanites. This is not an insignificant point. The capture of prisoners during warfare was becoming extremely important among the Maya during these years (and later). Thus this particular invasion fits one of the Mesoamerican patterns. Hassig has noted that forceful destructions were often part of the need to hold power, and the previous defeat at the hands of the Nephites may have been sufficient reason to warrant this type of bloody retaliation.
That this is a retaliation raid, and not a war of conquest is very clear by the actions of the Lamanites. Not only do they attack and destroy the city of Ammonihah, but they take their captives and immediately begin the return. There is no attempt to gain and hold a territory, nor to set up any type of dependence. Thus the function of war was both retaliation and the collection of prisoners. When those ends were met, the army retreated.
It is not surprising that the Nephites would want to gain the return of the prisoners, not simply because they were Nephites, but because of the nature of prisoners in the Maya territories at this time. The fate of these prisoners was likely torture and sacrifice, as well as political currency and prestige. The recovery of those people would deny the Lamanites much of the glory of their attack. [Brant Gardner, Book of Mormon Commentary, [http://www.highfiber.com/~nahualli/LDStopics/Alma/Alma16.htm], pp. 2-3]