One of the key advisers to US Secretary of Defense Pitt Hegsheth, Dan Caldwell, was removed from the Pentagon on Tuesday after being identified in leakage investigation, a US official told Reuters.

Caldwell was put on an administrative license for “unauthorized revelation”, the official said.

“The investigation is ongoing,” the official said, without giving details of the nature of the revelation, including whether it became a journalist or another person.

President Donald Trump’s government has adopted an aggressive stance against the leaks, an attempt by Hegschez in the Pentagon.

Memorandum on March 21st, signed by Hegschez, Joe Casper, was calling for a investigation into “recent unauthorized disclosures of national security information concerning sensitive communications”.

Casper’s memorandum left open the possibility of a lie detector (a duplicate), although it is not clear if this was applied to Caldwell.

Although Caldwell is not as well -known as other Pentagon officials, he played a crucial role as a Hegsheth adviser.

His name was heard in a leak of talks through the Signal app, revealed by The Atlantic magazine last month.

In that messaging, Hegschez had named Caldwell as the best personnel association for the National Security Council, in view of the preparation for attacks against Houthi in Yemen.

Caldwell had aroused Washington’s interest in his previous positions.

Earlier Marines, with a term in Iraq, Caldwell had stated, before taking on the Pentagon’s duties that America would be in a better position if the US forces had simply stayed in the country.

“I think the war in Iraq was a monstrous crime,” he told the Financial Times in December 2024.

He was also a skeptic of US military aid to Ukraine and supported US withdrawal from Europe.

The decision to put Caldwell on administrative leave is independent of the wave of layoffs that began after Hegschez took over the Pentagon in January.