Boris Theodore Pash (born Boris Fedorovich Pashkovsky; Russian: Борис Фёдорович Пашковский) 20 June 1900 – 11 May 1995) was a United States Army military intelligence officer. He commanded the Alsos Mission during World War II and retired with the rank of colonel.

Source: Boris Pash – Wikipedia

Vasily Mikhailovich Zarubin Василий Михайлович Зарубин (1894–1972) was a Soviet intelligence officer. In the United States, he used the cover name Vasily Zubilin and served as Soviet intelligence Rezident from 1941 to 1944. Zarubin’s wife, Elizabeth Zubilin, served with him.
https://en.wikipedia.org/wiki/Vasily_Zarubin

Stjepan Mesaros, best known as Steve Nelson (1903–1993), was a Croatian-born American political activist. Nelson achieved public notoriety as the political commissar of the Abraham Lincoln Brigade in the Spanish Civil War and a leading functionary of the Communist Party, USA. Nelson is best remembered for having been prosecuted and convicted under the Smith Act in 1953.
https://en.wikipedia.org/wiki/Steve_Nelson_(activist)

John Lansdale Jr. (9 January 1912 – 22 August 2003) was a United States Army colonel who was in charge of intelligence and security for the Manhattan Project.

John Lansdale Jr.
Lansdale is awarded the Legion of Merit by Major General Leslie Groves, the director of the Manhattan Project
Nickname(s)	Jack
Born	9 January 1912 Oakland, California
Died	22 August 2003(aged 91) Annapolis, Maryland
Buried	All Hallows Cemetery, Davidsonville, Maryland
Allegiance	United States of America
Service/branch	United States Army
Years of service	1941–1945
Rank	Colonel
Battles/wars	World War II: Allied Invasion of Germany
Awards	Legion of Merit Commander of the Order of the British Empire

A graduate of the Virginia Military Institute and Harvard Law School, Lansdale was commissioned as a second lieutenant in the United States Army Reserve in 1933. He was called up for active duty in June 1941, and was assigned to the Investigations Branch in the Office of the Assistant Chief of Staff, G-2 (military intelligence) of the War Department General Staff. He became involved with the Manhattan Project in 1942, eventually becoming Brigadier General Leslie Groves‘s special assistant for security. Lansdale coordinated the activities of the Manhattan Project’s field security teams with those of other agencies such as the FBI.

In April 1945, Groves sent Lansdale to Europe, where he worked with the Alsos Mission to secure 1,000 tons of uranium ore from the German Wirtschaftliche Forschungsgesellschaft(WiFO) plant in Stassfurt. He also participated in the planning and execution of Operation Harborage, in which a special Allied force went deep behind enemy lines, seized 1.5 tons of uranium ingots, and captured a number of German nuclear energy project scientists, including Carl Friedrich von Weizsäcker, Max von Laue, Karl Wirtz, Horst Korsching and Erich Bagge and Otto Hahn.

https://en.wikipedia.org/wiki/John_Lansdale_Jr.

https://en.wikipedia.org/wiki/MAUD_Committee

https://en.wikipedia.org/wiki/Tube_Alloys

The Uranium Committee was a committee of the National Defense Research Committee (NDRC) that succeeded the Advisory Committee on Uranium and later evolved into the S-1 Section of the Office of Scientific Research and Development (OSRD), when that organization absorbed the NDRC in June 1941, and the S-1 Executive Committee in June 1942. It laid the groundwork for the Manhattan Project by initiating and coordinating the early research efforts in the United States, and liaising with the Tube Alloys Project in Britain.
https://en.wikipedia.org/wiki/S-1_Executive_Committee

https://en.wikipedia.org/wiki/Chester_W._Nimitz