SAN DIEGO — One Navy sailor was killed and four others were injured when their van crashed Friday morning off Interstate 8 near Jacumba Hot Springs, authorities said. All five sailors — a woman and four men — were assigned to West Coast-based Naval Special Warfare units, the Navy said in a statement. The crash occurred as they were returning to San Diego from training at Camp Billy Machen, a desert training facility operated by Naval Special Warfare near Niland, southeast of the Salton Sea in Imperial County. Though it was not immediately clear if those involved were SEALs, the Navy describes …