Dear Mr. Fadeev,
Thank you for posting your question on History Hub!
We searched the National Archives Catalog and located the series Records Relating to the Activities of the Einwandererzentralstelle (EWZ), 1946-1994 (Microfilm Publication A3342) in the National Archives Collection of Foreign Records Seized (Record Group 242) that includes the subseries EWZ50. Roll J051 is part of that subseries, and, based on the information you provided, the file including information about the Zwetzich family should begin on frame 1536 of that microfilm roll. These records have not been digitized. For additional information about and access to these microfilmed records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at email@example.com.
More information about the Captured German Records may be located on the National Archives website.
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We hope this is helpful. Best of luck with your family research!