Defense Secretary Pete Hegseth’s adviser was escorted out of the Pentagon on Tuesday and put on administrative leave amid a probe into information leaks at the department.

Dan Caldwell, one of Hegseth’s senior advisers, was placed on leave after being identified during an ongoing investigation into the leaks at the Pentagon, a defense official told The Hill. 

It is unclear if Caldwell made the disclosure to a reporter or someone else. 

The Pentagon said last month that it started an investigation into “recent unauthorized disclosures of national security information” and that it would utilize polygraphs as part of the probe. 

“This investigation will commence immediately and culminate in a report to the Secretary of Defense,” Hegseth’s chief of staff Joe Kasper said in a March 21 memo. “The report will include a complete record of unauthorized disclosures within the Department of Defense and recommendations to improve such efforts.” 

Even outside the Defense Department, President Donald Trump’s administration has sought to crack down on information leaks. 

Caldwell, who was a public policy adviser at foreign policy-focused think tank Defense Priorities, was picked by Hegseth as the best point of contact in a Signal group chat in which top U.S. officials discussed upcoming strikes against Houthi rebels in Yemen, as was revealed by the Atlantic’s top editor, who was inadvertently added to the thread last month. 

Prior to serving at the Pentagon, Caldwell was the executive director of Concerned Veterans for America, a registered 501(c)(4) entity previously headed by Hegseth. 

Caldwell, a Marine Corps veteran who was deployed in Iraq, has come under criticism from some conservatives for believing the United States should downsize its military presence in Europe and some parts of the Middle East. 

“And I think our pursuit of primacy has ultimately made us weaker as a country,” Caldwell said late last year.  

“It has led us to undertake foreign misadventures like the Iraq War, to stay much longer in Afghanistan and to attempt to turn one of the most tribal nations in the world, a nation with a history of rejecting outside interference and influence for millennia, into a liberal democracy, to repeat the same mistakes again and again in places like Libya and Syria,” he said in an interview with the Financial Times published in December 2024. 

Reuters first reported on Caldwell being put on leave.

Ellen Mitchell contributed to this report.