KILLEEN, Texas (AP) — The U.S. Army is not publicly releasing its full investigation into a 2016 training session at a Texas military base that left nine people dead, arguing it has the right to protect privacy and not reveal its deliberations.

Eight soldiers and a West Point cadet died when their vehicle was swept into the rain-swollen Owl Creek on Fort Hood during a flash flood on June 2, 2016.

An internal investigation in the immediate wake of the deaths determined that decisions made by Staff Sgt. Miguel Angel Colonvazquez — who was among the dead — led to the accident at the sprawling Arm...