Pentagon deputy chief of staff Darin Selnick was removed from the Department of Defense headquarters on Tuesday. (Department of Defense | Getty Images)
Both Selnick and Caldwell worked for Concerned Veterans for America in the past, a group formerly led by Defense Secretary Pete Hegseth.
Reuters reported that Caldwell was placed on leave for an "unauthorized disclosure," as part of an investigation into leaked Pentagon documents.
The probe was announced last month, and concerned itself over "recent unauthorized disclosures of national security information."
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Pentagon officials Dan Caldwell, left, and Darin Selnick are being investigated amid the probe. (Concerned Veterans for America | Department of Defense)
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More information about the leak is unknown, and there is currently no evidence to connect Caldwell or Selnick to that leak.
Fox News Digital's Morgan Phillips contributed to this report.
Andrea Margolis is a writer for Fox News Digital and Fox Business. Readers can follow her on X at @andreamargs or send story tips to andrea.margolis@fox.com.
https://www.foxnews.com/politics/pentagon-deputy-chief-staff-second-hegseth-advisor-removed-amid-dod-leak-probe