Staff Sgt. Bryan C. Black, Staff Sgt. Jeremiah W. Johnson, Staff Sgt. Dustin M. Wright, and Sgt. La David T. Johnson died after their convoy was ambushed by a large force of ISIS fighters, which “began to envelop” the U.S. and Nigerien troops near the village of Tongo, according to a new unclassified Pentagon summary of the investigation into the Oct. 4, 2017, ambush in Niger.