U.S. Defense Secretary Pete Hegseth looks on, as President Donald Trump (not pictured) delivers remarks, in the Oval Office at the White House, in Washington, D.C., U.S., March 21, 2025.
Carlos Barria | Reuters
The Pentagon’s internal watchdog opened an investigation of Defense Secretary Pete Hegseth for using the Signal messaging app to discuss pending military strikes in Yemen in March with other senior Trump administration officials.
The probe will determine to what extent Hegseth and other Defense Department staff complied with existing rules over the “use of a commercial messaging application for official business,” the department’s Office of Inspector General said in a memo Thursday.
“Additionally, we will review compliance with classification and records retention requirements,” acting Inspector General Steven Stebbins told Hegseth in the memo.
The probe was launched at the request of Senate Armed Services Committee Chairman Roger Wicker, R-Miss., and Sen. Jack Reed of Rhode Island, the committee’s ranking Democrat, according to the memo.
Experts have raised concerns about whether the Signal chats violated the law.
The Signal group chat where Hegseth discussed strikes on Houthi targets included Vice President JD Vance, Hegseth, national security advisor Michael Waltz, as well as Secretary of State Marco Rubio, Director of National Intelligence Tulsi Gabbard, CIA Director John Ratcliffe, and Treasury Secretary Scott Bessent.
Hegseth gave the chat participants sensitive operational details, including the timing of the attacks and the weapons to be used.
Hegseth’s texts were revealed in a bombshell report last week by The Atlantic’s editor-in-chief Jeffrey Goldberg, who Waltz inadvertently added to the group chat.
The Trump administration has said that no classified information was discussed in the thread.
The Defense Department declined to comment on Stebbins’ investigation, citing longstanding policy. The White House did not immediately respond to a request for comment.
Waltz was at an Oval Office meeting with President Donald Trump on Wednesday, where the far-right activist Laura Loomer pressed the president to fire some of his national security aides, NBC News reported.
Trump fired six members of his National Security Council after that meeting, The New York Times reported Thursday.
Stebbins became the Pentagon’s acting watchdog after Trump fired Inspector General Robert Storch in January.
Stebbins was previously appointed principal deputy inspector general in April 2023, under President Joe Biden.