What happened to many Japanese Americans during the war & why did it happen

They were put into internment camps for the remainder of the war for fear of them being spies.

The internment of Japanese Americans in the United States during World War II was the forced relocation and incarceration in camps in the western interior of the country of between 110,000 and 120,000[5] people of Japanese ancestry, most of whom lived on the Pacific coast. 62 percent of the internees were United States citizens.[6][7] These actions were ordered by President Franklin D. Roosevelt shortly after Imperial Japan's attack on Pearl Harbor.[8]