Pentagon Chief Spokesperson Dana W. White speaks during a news briefing at the Pentagon April 14, 2018 in Arlington, Virginia.
Alex Wong/Getty Images
Pentagon Chief Spokesperson Dana W. White speaks during a news briefing at the Pentagon April 14, 2018 in Arlington, Virginia.
Now playing
01:48
Pentagon chief spokeswoman under investigation
Garret Ventry
Now playing
01:33
GOP adviser abruptly quits amid sex harassment claim
Getty Images
Now playing
01:49
Trump defends Kavanaugh amid allegations
WASHINGTON, DC - APRIL 21:  Rep. Chris Collins (R-NY) talks to reporters following a meeting with fellow members of Congress and representatives from the Donald Trump presidential campaign at the National Republican Club of Capitol Hill April 21, 2016 in Washington, DC. (Chip Somodevilla/Getty Images)
Chip Somodevilla/Getty Images
WASHINGTON, DC - APRIL 21: Rep. Chris Collins (R-NY) talks to reporters following a meeting with fellow members of Congress and representatives from the Donald Trump presidential campaign at the National Republican Club of Capitol Hill April 21, 2016 in Washington, DC. (Chip Somodevilla/Getty Images)
Now playing
02:34
GOP lawmaker indicted for insider trading
SAN DIEGO, CA - AUGUST 23: Rep. Duncan Hunter (R-CA) walks into the Federal Courthouse for an arraignment hearing on August 23, 2018 in San Diego, California. Hunter and his wife Margaret are accused of using more than $250,000 in campaign funds for personal use. (Photo by Sandy Huffaker/Getty Images)
Sandy Huffaker/Getty Images North America/Getty Images
SAN DIEGO, CA - AUGUST 23: Rep. Duncan Hunter (R-CA) walks into the Federal Courthouse for an arraignment hearing on August 23, 2018 in San Diego, California. Hunter and his wife Margaret are accused of using more than $250,000 in campaign funds for personal use. (Photo by Sandy Huffaker/Getty Images)
Now playing
03:19
GOP lawmaker blames wife in corruption case
Now playing
01:50
State Rep. resigns after screaming N-word
Rep. Jason Lewis
Now playing
02:53
GOP rep. defends prior comments on 'slut' women
In this Jan. 29, 2018, file photo, Missouri Gov. Eric Greitens speaks in Palmyra, Mo.
Jeff Roberson/AP
In this Jan. 29, 2018, file photo, Missouri Gov. Eric Greitens speaks in Palmyra, Mo.
Now playing
02:29
Missouri Gov. Eric Greitens indicted
 Eric Greitens Founder and CEO, The Mission Continues speaks at the Robin Hood Veterans Summit at Intrepid Sea-Air-Space Museum on May 7, 2012 in New York City.
Getty Images
Eric Greitens Founder and CEO, The Mission Continues speaks at the Robin Hood Veterans Summit at Intrepid Sea-Air-Space Museum on May 7, 2012 in New York City.
Now playing
00:44
Governor admits affair, denies blackmail
Now playing
02:22
Sex scandals in Washington through the years
Megan Barry
WZTV
Megan Barry
Now playing
01:11
Mayor admits affair with head of her security
 The White House is shown during departure by President Donald Trump for the congressional Gold Medal ceremony for former Senate Majority Leader Bob Dole at the U.S. Capitol January 17, 2018 in Washington D.C. (Al Drago-Pool/Getty Images)
Pool/Getty Images
The White House is shown during departure by President Donald Trump for the congressional Gold Medal ceremony for former Senate Majority Leader Bob Dole at the U.S. Capitol January 17, 2018 in Washington D.C. (Al Drago-Pool/Getty Images)
Now playing
00:51
Second WH aide resigns after abuse accusations
UNITED STATES - DECEMBER 13: Rep. Blake Farenthold, R-Texas, attends a House Judiciary Committee hearing in Rayburn Building on the Justice Department's investigation of Russia's interference in the 2016 election featuring testimony by Deputy Attorney General Rod Rosenstein on December 13, 2017. (Photo By Tom Williams/CQ Roll Call) (CQ Roll Call via AP Images)
Tom Williams/AP
UNITED STATES - DECEMBER 13: Rep. Blake Farenthold, R-Texas, attends a House Judiciary Committee hearing in Rayburn Building on the Justice Department's investigation of Russia's interference in the 2016 election featuring testimony by Deputy Attorney General Rod Rosenstein on December 13, 2017. (Photo By Tom Williams/CQ Roll Call) (CQ Roll Call via AP Images)
Now playing
01:30
Ex-Farenthold aide felt pressured, source says
Now playing
01:02
Congressman calls female colleagues 'eye candy'
Former Congressman Anthony Weiner (D-N.Y.), center, leaves federal court following his sentencing, Monday, Sept. 25, 2017, in New York. Weiner was sentenced to 21 months in a sexting case that rocked the presidential race.
Mark Lennihan/AP
Former Congressman Anthony Weiner (D-N.Y.), center, leaves federal court following his sentencing, Monday, Sept. 25, 2017, in New York. Weiner was sentenced to 21 months in a sexting case that rocked the presidential race.
Now playing
01:04
A timeline of Anthony Weiner's sexting scandals
Pool
Now playing
00:56
Boy demands apology from Mike Pence
(CNN) —  

Chief Pentagon spokeswoman Dana White is leaving her post, a move that coincides with Secretary of Defense James Mattis stepping down but also comes amid an internal Defense Department investigation into her conduct.

“I appreciate the opportunity afforded to me by this administration to serve alongside Secretary Mattis, our Service members and all the civilians who support them,” White tweeted Monday. “It has been my honor and privilege. Stay safe and God bless.”

White also sent a farewell message to Defense Department public affairs personnel Monday.

“It is with a heavy heart that I have submitted my letter of resignation to Secretary Mattis. I am grateful to the administration for giving me the opportunity to serve alongside Secretary Mattis, the brave men and women in uniform, and all of the civilians who support them,” the message read, according to a copy obtained by CNN.

On Tuesday, Charles Summers Jr., a principal deputy assistant to the secretary of defense in White’s office, will assume the role of acting assistant to the secretary of defense for public affairs, according to the Pentagon.

White’s departure comes as the department’s inspector general investigates allegations of retaliation against staff members after she used some of them to conduct her personal errands and business matters.

In August, CNN reported that White, a Trump administration political appointee, was under investigation by the inspector general after multiple complaints were filed against her.

White is alleged to have misused support staff, asking them to fetch her dry cleaning, run to the pharmacy for her and work on her mortgage paperwork, among other things. Staffers also accused White of inappropriately transferring personnel after they filed complaints about her.

White became the Pentagon’s chief spokeswoman in April 2017 and reported directly to Mattis. The defense secretary’s last day at the Pentagon also was Monday.

White used to hold regular televised press briefings, but has not appeared in one since May. It is not clear if her absence from briefings is related to the investigation. Reporters have been told the White House wanted to see more briefings by senior uniformed officers.

After a months-long pause in on-camera briefings, Mattis selected Burke Whitman, a two-star major general in the Marine Corps, to act as a uniformed spokesman for the Defense Department.

While White remained in her role up until Monday’s announcement, the expectation was that Whitman would replace her as the Pentagon’s regular on-camera briefer.

The decision to appoint Whitman was controversial because the military is supposed to remain outside the political arena, and with a member of the military acting as spokesperson, reporters will not be able to ask questions about the political aspects of decision-making.