EXCLUSIVE-Top Hegseth adviser Dan Caldwell put on leave in Pentagon leak probe

By Phil Stewart

WASHINGTON, April 15 (Reuters) - One of U.S. Defense Secretary Pete Hegseth's leading advisers, Dan Caldwell, was escorted from the Pentagon on Tuesday after being identified during an investigation into leaks at the Department of Defense, a U.S. official told Reuters.

Caldwell was placed on administrative leave for "an unauthorized disclosure," the official said, speaking on condition of anonymity. The decision has not been previously reported.

"The investigation remains ongoing," the official said without providing details about the nature of the alleged disclosure, including whether it was made to a journalist or to someone else.

A March 21 memo signed by Hegseth's chief of staff, Joe Kasper, requested an investigation into "recent unauthorized disclosures of national security information involving sensitive communications."

Kasper's memo left open the possibility of a polygraph, although it was unclear if Caldwell was subject to one.

Although Caldwell is not as well known as other senior Pentagon officials, he has played a critical role as an adviser to Hegseth.

His importance was underscored in a leaked text chain on Signal disclosed by The Atlantic magazine last month.

In it, Hegseth named Caldwell as the best staff point of contact for the National Security Council as it prepared for the launch of strikes against the Houthis in Yemen.