Early on 9 July 1917, the gunpowder magazine at the Naval Ammunition Depot on Mare Island, California, exploded, flattening several nearby buildings and killing six. Immediately, U.S. Navy officials blamed German sabotage, but the investigation proved inconclusive.
A century later, German responsibility, first assumed in 1918 and republicized in 1937, has become regarded as fact, with a dozen books and papers repeating the claim. A close examination of the historical record, however, reveals the claim to be false—and suggests an entirely different explanation.
German Agents Afoot in America
In early 1916, 34-year-old German-American private detective and former U.S. Marine Kurt Jahnke walked into the San Francisco office of the Justice Department’s Bureau of Investigation and declared that a German-American was planning an attack on Mare Island.1 Allegations of German espionage at Mare Island had broken in the press earlier that day, and news stories about German sabotage in New York had been circulating for several months.
1. Henry Landau, The Enemy Within: The Inside Story of German Sabotage in America (New York: G. P. Putnam’s Sons, 1937), 34; U.S. Army, Military Intelligence, Mixed Claims Commission, memo (n.d.) marked Exhibit B, Witzke Courts-Martial Records, Record Group (RG) 76, Box 6, National Archives and Records Administration (NARA), Lanham, MD; and Richard B. Spence, “K. A. Jahnke and the German Sabotage Campaign in the United States and Mexico, 1914–1918,” The Historian 59, no. 1 (September 1996): 89–112.
2. Reinhard R. Doerries, Hitler’s Last Chief of Foreign Intelligence: Allied Interrogations of Walter Schellenberg (London: Frank Cass, 2003); Landau, The Enemy Within, 23–34; “Efforts Made to Dynamite Piers, Police Scent Plot to Blow Up the Non-Union Dock Workers in Seattle,” The Sacramento Union, 18 August 1916; Matthew Erin Plowman, “The British Intelligence Station in San Francisco During the First World War,” Journal of Intelligence History 12, no. 1 (2013): 1–20; and Robert Derencin, “Secret Naval Supply System of the German Imperial Navy in WWI.”
3. Landau, The Enemy Within, 34–35; “The Sinking of SMS Dresden, 14 March 1915.”
4. D. A. Sheehy, “A Résumé of the Log of H.M.S. ‘Orama,’ 1914–1917,” transcripts.sl.nsw.gov.au/page/404272/view, 39; “Merchantman Chased by German Cruiser—South American Adventures,” The (Melbourne, Australia) Argus, 12 March 1915; Landau, The Enemy Within, 10–11; 127; and Greg H. Williams, The United States Merchant Marine in World War I: Ships, Crews, Shipbuilders and Operators (Jefferson, NC: McFarland, 2017), 21.
5. National Park Service, “Historic American Buildings Survey: Mare Island Naval Shipyard,” loc.gov/pictures/collection/hh; Commandant, Mare Island,to Secretary of the Navy, 29 September 1917, “Report of Board to Investigate Explosion at Naval Ammunition Depot,” RG 125, Box 98, Case 7038, NARA, Washington, DC.
6. Jeffery Dorwart, The Office of Naval Intelligence: The Birth of America’s First Intelligence Agency, 1865–1918 (Annapolis, MD: Naval Institute Press 1979); “Code Book Trial Ends,” The Washington Post, 13 February 1916.
7. Mare Island Naval Shipyard Public Works Officer to Commandant, 14 July 1917, report showing condition of buildings at the Naval Ammunition Depot following 9 July 1917 explosion, RG 71, Box 40, NARA, Washington, DC; D. Benveniste, “The Early History of Psychoanalysis in San Francisco,” Psychoanalysis and History 8, no. 2 (July 2006): 195–233.
8. Commandant, Mare Island, “Report of Board”; “Nine Killed When Magazine Lets Go at Mare Island,” South Bend News-Times, 9 July 1917.
9. Robert L. Koenig, The Fourth Horseman: One Man’s Secret Mission to Wage the Great War in America (Cambridge, MA: Perseus Books, 2006); Landau, The Enemy Within, 102; and Lothar Witzke letter to LT Robert W. Hicks Jr., 23 March 1934, RG 76, PI 143/76 NARA, Lanham, MD.
10. “Mare Island Explosions Believed Due to Plot; Navy Officials Probing Disaster; Six Killed, 31 Injured,” Honolulu Star-Bulletin, 9 July 1917; Commandant, Mare Island, “Report of Board”; and “6 Dead, 38 Injured at Mare Island,” Sausalito News, 14 July 1917.
11. Commandant, Mare Island, “Report of Board.”
12. Intelligence Officer, U.S. Army Third District, Western Department, “Report—German Activities in the U.S. and Mexico,” 28 August 1917, RG 76, Box 5, “Documents relating to German sabotage activities, 1915–18,” NARA, Lanham, MD; Landau, The Enemy Within, 170–73; and Koenig, The Fourth Horseman.
13. Landau, The Enemy Within, 120, 171.
14. Paul B. Altendorf, “On Secret Service in Mexico,” Chicago Daily Tribune, 19 November 1919; Military Intelligence Branch Memo, 17 July 1918, addressed to CAPT. Edward McCauley, Office of Naval Intelligence; and U.S. Navy Bureau of Navigation, Officers and Enlisted Men of the United States Navy Who Lost Their Lives During the World War, from April 6, 1917 to November 11, 1918 (Washington, DC: U.S. Government Printing Office, 1920), 37.
15. Landau, The Enemy Within, 117, 223.
17. Langley’s San Francisco Directory, 1889, archive.org/details/langleyssanfranc1889sanf; Commandant, Mare Island, “Report of Board”; and Report of the Secretary of the Navy (Washington, DC: U.S. Government Printing Office, 1892), 296, bls.gov/opub/uscs/1918-19.pdf.
18. Damstedt-Hathaway wedding announcement, San Francisco News Letter and California Advertiser, 2 January 1915; “Neil C. Damstedt;” and Commandant, Mare Island, “Report of Board.”
19. Commandant, Mare Island, “Report of Board”; Woodmen of the World Life Insurance Society Records, 17 April 1920, Universal Whole Life Certificate, “If the member holding this certificate shall . . . die . . . by his own hand . . . the certificate shall be null and void,” digital.library.txstate.edu/bitstream/handle/10877/9710/100_100_woodman.pdf.
20. Steven Stack and David Lester, “The Suicide of Ajax: A Note on Occupational Strain as a Neglected Factor in Suicidology,” in Suicide and the Creative Arts (New York: Nova Science Publishers, 2009), 49–53; Steven Stack and Ira Wasserman, “Economic Strain and Suicide Risk: A Qualitative Analysis,” Suicide and Life-Threatening Behavior 37, no. 1 (February 2007): 103–112; Toshiki Shioiri et al., “Incidence of Note-Leaving Remains Constant Despite Increasing Suicide Rates,” Psychiatry and Clinical Neurosciences 59, no. 2 (April 2005): 226–28; and Mallikarjun S. Ballur et al., “Strategic Evaluation of Suicide Notes,” International Journal of Current Research and Review 6, no. 17 (September 2014): 21–24.
21. U.S. Navy Bureau of Ordnance, Navy Ordnance Activities: World War, 1917–1918 (Washington, DC: U.S. Government Printing Office, 1920), 90; U.S. Navy Bureau of Navigation, Officers and Enlisted Men of the United States Navy Who Lost Their Lives During the World War, 37.