 After extensive air and naval gunfire bombardment, the United States Marine Corps launched an amphibious assault on Iwo Jima starting February 19.The American forces, who knew that Nishi was an enemy commander, broadcast daily appeals for him to surrender, stating that the world would regret losing "Baron Nishi"; Nishi never responded to those appeals.The American intelligence officer responsible for this attempt was Sy Bartlett of the 315th Bomber Wing out of Guam, who would later write the novel and film screenplay "Twelve O'Clock High".