In August 1920, Haan left Hawaii to spend a year preparing for the ministry at the Salvation Army Training School in San Francisco, California.
[3] Haan successfully lobbied the Justice Department to exclude Koreans from the internment of Japanese Americans, despite Korea being legally part of Japan at the time.
[3] In the summer of 1942, Haan circulated a "secret report" to American newspapers stating that Japanese leaders Hideki Tojo and Koki Hirota had been wounded by gunshots from Korean patriot Park Soowon.
[5] On May 5, 1943, Haan appeared before Chairperson Samuel Dickstein’s House Immigration Committee on the repeal of the Chinese Exclusion Law.
He gave testimony that his network of spies in East Asia had discovered evidence of the Japanese government's plan to end the war in China and re-deploy its naval assets to convoy a force of over 100,000 seasoned troops to invade Crescent City, California, "before Christmas".