William Perl, whose real name was William Mutterperl, was a student at the City College of New York. As a member of the Steinmetz Club, the campus branch of the Young Communist League, he met and befriended Julius Rosenberg, Morton Sobell and Joel Barr. Perl graduated with a degree in engineering in 1939 and in 1940 began working for the National Advisory Committee for Aeronautics (NACA) at their Langley Army Air Base research facility. In 1944 Perl transferred to the NACA Lewis Flight Propulsion Laboratory in Cleveland. Both jobs provided Perl with access to extensive classified materials. NACA sent Perl to Columbia University to pursue doctoral studies in Physics. While at Columbia Perl lived in the same Morton Street apartment where Barr and Alfred Sarant had lived.
Following his doctorate work at Columbia Perl returned to Cleveland to work on a jet propulsion project related to supersonic flight. Perl was nearly given a position with the Atomic Energy Commission when his connection with Barr and Sarant, suspected Communists, was turned up by a security check. In July of 1950 Vivian Glassman, Barr's fiancée, visited Perl in Cleveland to give him $2000, and advising him to go to Europe. Unlike Barr and Sarant, Perl decided not to flee the country, perhaps thinking he might be able to salvage his career.
Perl appeared before the Rosenberg Grand Jury in the summer of 1950, denying any relationship with Julius Rosenberg, Morton Sobel, Max Elitcher, and the Sidoroviches. The FBI suspected Perl of providing information to the Soviets and he was arrested on March 15, 1951. Evidence that Perl had engaged in espionage activities was mostly circumstantial so the FBI was forced to settle for perjury charges. In May 1953 a jury found Perl guilty of two counts of perjury for lying about his relationship with Rosenberg and Sobel. He was acquitted of two other counts. Perl served two concurrent 5 year sentences at the New York House of Detention, maintaining his innocence in any espionage plot.
Decoded Soviet documents, the "Verona files," provide compelling evidence that Perl was indeed a spy. A June 16, 1944, cable to Moscow reports that Perl had given the KGB "material information about air units for new aircraft." The information was thought so valuable that Perl was given a bonus of $500. The data he provided aided the Soviets in the unique tail-fin design of the MiG-15 fighter used in the Korean War.
William Perl is referenced in the following Venona project decryptions:
- 717 KGB New York to Moscow, 10 May 1944;
- 732 KGB New York to Moscow, 20 May 1944
- 854 KGB New York to Moscow, 16 June 1944, p.1
- 854 KGB New York to Moscow, 16 June 1944, p.2
- 1048 KGB New York to Moscow, 25 July 1944, p.1
- 1048 KGB New York to Moscow, 25 July 1944, p.2
- 1251 KGB New York to Moscow, 2 September 1944
- 1314 KGB New York to Moscow, 14 September 1944
- 1491 KGB New York to Moscow, 22 October 1944
- 1536 KGB New York to Moscow, 28 October 1944
- 1797 KGB New York to Moscow, 20 December 1944, p.1
- 1797 KGB New York to Moscow, 20 December 1944, p.2
- 954 KGB Moscow to New York, 20 September 1944
- 154 KGB Moscow to New York, 16 February 1945, p.1
- 154 KGB Moscow to New York, 16 February 1945, p.2
- 224 Moscow to New York, 13 March 1945
- 305 KGB Moscow to New York, 1 April 1945
Douglas Linder, A Trial Account (2001).