reporter: the deadly ambush in this remote african village happened more than two weeks ago. but tonight, the pentagon is still not providing a full and cogent narrative of how four american soldiers died after being attacked by an overwhelming force of more than 50 militants. officials said the full investigation, only announced today, is still ongoing. subsaharan africa is a very difficult place to operate. so, we will we ll investigate this. we ll have conclusions and those conclusions will be presented. i m not prepared to go further. reporter: two key questions remain tonight. one, did the unit have the proper advance intelligence and backup air and ground support in case something went wrong? officials said the unit did not expect to be in combat. over the last six months, we have conducted 29 partnered patrols in this general area without contact of any kind. reporter: a second question. did sergeant la david johnson get left behind when the rest of the unit pulled o