Under subpoena in 1948 , he testified in what became Alger Hiss 's perjury ( espionage ) trials ( 1949 -- 1950 ) .
He became an outspoken anti-communist ( all described in his 1952 memoir Witness ) .
Under subpoena in 1948 , he testified in what became Alger Hiss 's perjury ( espionage ) trials ( 1949 -- 1950 ) and he became an outspoken anti-communist ( all described in his 1952 memoir Witness ) .