 As the only FBI field agent in Washington, D.C., fluent in Spanish in 1954, Rudd participated in the interrogation of the Puerto Rican nationalists involved in the attack on the US House of Representatives that year.His report impressed Director J. Edgar Hoover, who offered Rudd his next choice of assignment, which he received as U.S. legal attaché at the U.S. Embassy in Mexico City, where he served from 1960 to 1970.When assassin Lee Harvey Oswald shot and killed President John F. Kennedy in Dallas, Texas, on November 22, 1963, Rudd was ordered by Hoover to collect from the Mexican government their law enforcement and intelligence files on Lee Harvey Oswald, including files relating to Oswald's connections to the pro-Fidel Castro Fair Play for Cuba Committee, Oswald's several trips to and from Cuba, and his arrest in Mexico City.