WASHINGTON — The Pentagon’s probe into classified information leaks has widened to include two additional aides to Defense Secretary Pete Hegseth and his deputy, according to officials on Wednesday (April 16). On Tuesday, Reuters reported that senior adviser Dan Caldwell had been escorted out of the Pentagon and placed on administrative leave following what a U.S. official described as an “unauthorized disclosure.”

Following this, two other aides—Darin Selnick, Hegseth’s deputy chief of staff, and Colin Carroll, chief of staff to Deputy Defense Secretary Steve Feinberg—were also placed on administrative leave. Officials noted that more personnel could be implicated as the investigation continues. President Trump’s administration has taken a hardline stance on leaks, a stance fully supported by Hegseth since assuming leadership at the Pentagon.

A memo dated March 21, signed by Hegseth’s chief of staff Joe Kasper, called for a formal probe into the leaks involving sensitive national security communications. It also mentioned the possibility of using polygraph tests, though it's unclear whether Caldwell, Selnick, or Carroll were tested. Selnick, a retired Air Force officer, had recently taken over as deputy chief of staff and previously led personnel and readiness policy advisement. Carroll, a Marine Corps veteran, had worked with AI defense firm Anduril Industries. Politico had earlier reported their administrative leave.

Caldwell, a key figure in Hegseth’s inner circle, was highlighted in a leaked Signal text thread—published by The Atlantic—where Hegseth referred to him as the best point of contact for the National Security Council in preparation for strikes on Yemen's Houthis. Caldwell has previously made headlines for views considered isolationist by critics but praised by supporters as a recalibration of U.S. defense goals. A veteran of the Iraq War, he once stated the U.S. would have been better off not sending troops there, calling the war a “monstrous crime” in a Financial Times interview in December 2024. He was also critical of U.S. military aid to Ukraine and pushed for a scaled-back presence in Europe.

The administrative leave of Caldwell, Selnick, and Carroll is distinct from a series of high-profile firings initiated by Hegseth since his appointment in January. Those dismissals included senior military leaders such as the Joint Chiefs chairman, Navy’s top admiral, the head of U.S. Cyber Command, and senior military legal officials. Reuters also recently reported the firing of the U.S. military representative to NATO.

Disclaimer: This image is taken from Reuters.