The FBI's own FOIA-released file confirms Ludwik Rajchman was served a congressional subpoena on February 19, 1957, issued by the Senate Internal Security Subcommittee under James O. Eastland — not Joseph McCarthy's own subcommittee

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A New York FBI field-office memo, dated the night of the event, records that Lyle H. Munson — named in the same file as "consultant to the Senate Internal Security Subcommittee" — tried to hand Ludwik Rajchman a paper in the lobby of the Westbury Hotel in New York. Rajchman refused it and went back to his room; a bellhop then found the document on the lobby floor. The hotel's own executive assistant manager, Alfred Hayhurst, retrieved it and identified it: "Hayhurst then obtained the paper from the bellhop and found that it was a subpoena for the subject to appear at the Senate Office Building at 10 a.m., February 20, 1957." Rajchman, then Polish delegate to UNICEF, told Hayhurst "it could not possibly be" a valid subpoena because he was a diplomat, but came down to the lobby, took the document, and said he would refer it to his ambassador. A companion FBI teletype identifies the issuing authority precisely: the subpoena was "issued over the signature of James O. Eastland, Chairman, Senate Internal Security Sub-Committee of the Judiciary Committee," dated February 18, 1957, calling for Rajchman's appearance on February 20 at Room 319 of the Senate Office Building.

This corrects a widely repeated flattening. Wikipedia's "Ludwik Rajchman" article states only that he "was subpoenaed in the McCarthy period" — true as an era descriptor, but the primary record shows the subpoenaing body was the Senate Internal Security Subcommittee (SISS) of the Judiciary Committee, a separate, contemporaneous anti-communist committee from Joseph McCarthy's own Permanent Subcommittee on Investigations. See claim-ludwik-rajchman-squeezed-out-by-both-cold-war-blocs for the broader claim this settles, and James O. Eastland for the chairman whose name the popular framing omits.