Why were people sent to internment camps during WWII?

After the Japanese bombed Pearl Harbor, many people living in the US developed a fear and hatred towards people of Japanese heritage. Many Americans thought that Japan had spies on US land. Due to the growing fear of spies and other possible attacks on US soil, the US President at the time, Franklin Roosevelt, decided to imprison everyone living in the US with Japanese heritage, whether they were immigrants from Japan or US citizens.

After Pearl Harbor Americans found it hard to trust anyone who was different. They wanted to make sure that the Japanese in country could not contact others outside of the country.