The three highest-ranking aides of Defense Secretary Pete Hegseth, who were initially suspended during the Signal group chat investigation, have now each been fired.

Darin Selnick, the deputy chief of staff at the Pentagon, and Dan Caldwell, a senior advisor to Defense Secretary Hegseth, were both placed on administrative leave as the investigation unfolded.

Colin Carroll, chief of staff to Deputy Defense Secretary Stephen Feinberg, was suspended a day later. 

All three have since been let go and Hegseth’s Chief of Staff Joe Kasper is set to resign in the coming days, according to Politico. 

DailyMail.com has reached out to the Pentagon for comment. 

Kasper’s departure is especially curious, as he put in the request for an investigation into multiple leaks out of the Pentagon last month.  

‘Joe didn’t like those guys,’ an anonymous source said of Kasper’s relationship with Caldwell, Selnick and Carroll. 

‘They all have different styles. They just didn’t get along. It was a personality clash.’ 

The departures now leave a huge void of several key roles in Hegseth’s Defense Department. 

‘There is a complete meltdown in the building, and this is really reflecting on the secretary’s leadership,’ a former defense official said. 

‘Pete Hegseth has surrounded himself with some people who don’t have his interests at heart.’ 

President Donald Trump has expressed strong disapproval towards individuals who divulge sensitive information, especially in regard to leaks concerning his administration, and has mandated efforts to identify and address such breaches.

Caldwell and Selnick were put on administrative leave and escorted out of the Pentagon by security on Tuesday. 

Carrol was suspended a day after two other political appointees were shown the door, Politico reported.

The internal Pentagon investigation is looking into allegations of unauthorized disclosures of information. 

‘This is a purge of people who had disagreements with the Pentagon chief of staff,’ a defense source told CNN.

Carroll, a former Marine Corps intelligence officer with deep AI expertise, served in Afghanistan. He is a graduate of the United States Naval Academy.

Ahead of his tenure at the Pentagon, Carroll worked at Anduril, a defense contractor that specializes in autonomous systems.

And he was fired by the Biden administration for creating a hostile environment while chief operating officer of the Pentagon’s former Joint Artificial Intelligence Center. 

The inspector general conducted an investigation in 2021 into how Carroll treated his employees, sources told Politico last month.

The staff told the IG that Carroll said they ‘weren’t smart,’ ‘dumb’ or ‘idiots.’ He was also said to have called colleagues ‘f***ing idiots’ or ‘morons.’ 

Carroll told the outlet he was asked to resign but claimed he was winnowing down DOD projects, which frustrated some colleagues, and fighting against an entrenched bureaucracy.

‘I was three years too early in attempting to drive the necessary revolutionary change required to deliver tangible outcomes to warfighters,’ Carroll said.

The leak investigation at the Pentagon began on March 21 when Hegseth’s chief of staff Kasper ordered the probe.

The probe included military operational plans for the Panama canal, a second carrier headed to the Red Sea, the pausing the collection of intelligence to Ukraine, and the leak that Elon Musk’s would meet with Hegseth about the U.S. war plans for China, an official told Politico.

Kasper said the probe would examine ‘recent unauthorized disclosures of national security information’ and said polygraphs would be used.

‘The use of polygraphs in the execution of this investigation will be in accordance with applicable law and policy,’ he wrote. ‘This investigation will commence immediately and culminate in a report to the Secretary of Defense.’

He noted that ‘information identifying a party responsible for an unauthorized disclosure’ would be referred for criminal prosecution.’

Kasper ordered the probe one day after the New York Times reported the Pentagon set up a briefing with Elon Musk on a potential war with China.

Caldwell played a critical role as an adviser to Hegseth. 

He was the staff member designated as Hegseth’s point person in the Signal messaging chat that top Trump administration national security officials, including the defense secretary, used to convey plans for a military strike against Houthi militants in Yemen.

The chat, set up by national security adviser Michael Waltz, included a number of Cabinet members and came to light because Jeffrey Goldberg, editor-in-chief of The Atlantic, was accidentally added to the group.

Caldwell and Hegseth have a longtime friendship, going back to Hegseth’s time as the head of Concerned Veterans for America, a nonprofit. Caldwell worked at CVA beginning in 2013 as policy director and later as executive director. 

Additionally, Caldwell was by Hegseth’s side on Capitol Hill as the former Fox News host fought to keep his nomination alive during questions about his treatment of women. 

Selnick also performed the duties of the under secretary of Defense for personnel and readiness. He served in the White House and the Department of Veterans Affairs in the first Trump administration. 

And he also has ties to Concerned Veterans for America, where he served as a senior adviser.

All three suspended aides are close in age and share the same isolationist view of foreign policy. That view is also shared by Vice President J.D. Vance and Don Trump Jr., the president’s oldest son.