Why were many japanese americans forced to live in internment camps during world war ii?

 As a result of anti-Japanese prejudice and fear.

They were being held prisoner because of the fear that they would give information to the Japanese or attack the U.S.  Suspicious of anyone of Japanese heritage, the government restricted the civil liberties of Japanese Americans.  In February, 1942, President Roosevelt issued Executive Order 9066, which allowed the Secretary of War to designate certain areas as military zones.  FDR's executive order set the stage for the relocation of Japanese-ancestry persons to internment camps.  By June of 1942, over 100,000 Japanese Americans were sent to such internment camps.

Because of the red scare which thought they were going to try to make america a communist country. and the american people were afraid the they were still loyal to japan and that they may attack us on our home front so we locked them in a arg camp set up but they were not tortured. 

hope this answers your question.

Democracy and darwinism would be my answer.