 When the last officer reached safety, the officers opened a massive barrage from machine guns, mortars, and grenades on the prisoners within D Block, where the prison authorities erroneously thought one of the armed convicts was holed up.They eventually figured out that the rebellious prisoners were confined to the main cellhouse and ceased their attack until further tactics were worked out.The Marines, led by World War II Veteran, Warrant Officer Charles Lafayette Buckner, IX implemented a plan to drive the armed convicts into a corner with tactics they had perfected against entrenched Japanese resistance during the Pacific War.