The FBI has been illegally spying on people since the 1930s. The FBI took my maternal grandfather into custody on December 8, 1941 and held him in Fort Abraham Lincoln in North Dakota without charges for over a year. Then they released him without any charges without explanation or apologies.
Franklin Roosevelt cracked down after Pearl Harbor and the Republicans made a lot of noise at the time those considered “isolationists” were targeted by the US Justice Department.
After the mid-terms in 1942 things were eased a bit.