Staff Sgt. Dan Bevell, an Army diver assigned to the Defense POW/MIA Accountability Agency (DPAA), demonstrates how to search an underwater grid frame on a barge in the Gulf of Tonkin off the coast of Northern Vietnam, May 22, 2015. Bevell is part of an underwater recovery team searching for two aviators who are believed to have crashed in the area during the Vietnam War. Once the grid frame is secured to the ocean floor, divers from Mobile Diving and Salvage Unit ONE dredge inside the grid, and members of the joint recovery team sift through the dredged material in search of identifying evidence. (U.S. Navy photo by Mass Communication Specialist 1st Class Brett Cote/RELEASED)