You might do well to start with Joseph McCarthy, J. Edgar Hoover, and Roy Cohn, who were well known for their anti-communist attitudes and participated, to varying degrees, in the House Un-American Activities Committee, which is probably the most memorable institution that the "red scare" produced. McCarthy's telegram to President Truman sort of kicked the "red scare" off and it pretty much encapsulates the paranoia and suspicion that characterized the era. The National Archives have lots of first hand sources from the era and you can probably find Paul Robeson and Pete Seeger's testimonies from the hearings kicking around somewhere, though they were both sympathetic to communism. Additionally, HUAC produced an anti-communist propaganda film called Operation Abolitio and I'm sure you'll find lots of information there. I'd also check out the trials of Julius and Ethel Rosenberg for treason, as well as Alger Hiss. It's worth noting that the US experienced an early "red scare" after the October Revolution and committees similar to HUAC existed and continued to combat the perceived threat of communism in the United States.