An aide to Sen. Kirsten Gillibrand, a 2020 Democratic presidential candidate and an advocate of the #MeToo movement, resigned in protest last summer over how the senator’s office handled her accusations of sexual harassment against a senior staffer, according to a report on Monday.

The woman, who was not identified in the report by Politico, filed a sexual harassment complaint last July accusing the aide of making unwelcome advances and crude remarks about other women in the office and potential female hires.

Less than three weeks later, the woman said, the man, identified in the report as Abbas Malik, retaliated against her for making the complaint.

She told Gillibrand’s chief of staff, Jeff Fassler, that she was stepping down because of the way the investigation was handled, the report said.

The woman sent a letter in an email dated Aug. 30, 2018, to Gillibrand, Fassler and Keith Castaldo, the senator’s chief counsel, saying she was disheartened at how the investigation into her accusations was conducted because Gillibrand had been so vocal about supporting sexual harassment victims.

“I trusted and leaned on this statement that you made: ‘You need to draw a line in the sand and say none of it is O.K. None of it is acceptable.’ Your office chose to go against your public belief that women shouldn’t accept sexual harassment in any form and portrayed my experience as a misinterpretation instead of what it actually was: harassment and ultimately, intimidation,” the woman wrote in the letter.

Gillibrand, a staunch advocate of the #MeToo movement in Congress, was one of the first senators to call for then-Sen. Al Franken to step down over allegations of sexual assault.

She issued a statement to Politico defending her office’s handling of the investigation.

“As I have long said, when allegations are made in the workplace, we must believe women so that serious investigations can actually take place, we can learn the facts, and there can be appropriate accountability,” Gillibrand said. “That’s exactly what happened at every step of this case last year. I told her that we loved her at the time and the same is true today.”

Malik, a military adviser to the senator, kept his job despite the allegations, but Politico found additional claims of inappropriate behavior, including him making a “joke” about rape to a female colleague.

After being presented with the new claims, Gillibrand’s office launched a new investigation and fired Malik last week.

He did not respond to a request for comment from Politico.

The Post was unable to contact Malik despite repeated attempts.

The woman who made the complaints told Politico in an interview that Gillibrand’s staffers didn’t take her claims seriously.

“When I had the courage to speak up about my harasser, I was belittled by her office and treated like an inconvenience,” the woman said. “She kept a harasser on her staff until it proved politically untenable for her to do so.”