The bombing of Pearl Harbor by Japan in December 1941 had set in motion a series of events and decisions that led to what has been called the worst violation of constitutional rights in American history: the expulsion and imprisonment of 110,000 persons of Japanese ancestry from the U.S. West Coast. Two thirds of them were American citizens.
The U.S. government wasted no time in clamping down on the 9,600 Japanese Americans in King County. The FBI arrested Issei (first generation Japanese) and a few Nisei (second generation), including Buddhist priests, Japanese language teachers, and officials and leaders of community organizations.
By the end of March, 1942, sites had been determined for "assembly centers," temporary prison camps to be used as holding centers for persons of Japanese ancestry until the people could be moved to more permanent "relocation centers." At the time, 14,400 Japanese and Japanese Americans lived in Washington state, 9,600 of them in King County. The Japanese population of Seattle was nearly 7,000.
A total of 12,892 persons of Japanese ancestry from Washington state were incarcerated. Seattle and Puyallup Valley Japanese were sent to the Puyallup "assembly center" and then onto Minidoka in Idaho.