A 15-year veteran of the U.S. Capitol Police filed a lawsuit against the department Wednesday alleging sex and disability discrimination and retaliation, claiming she was wrongfully dismissed from the elite and male-dominated K-9 unit during training after mistreatment by her supervisor.

Mauricia Van Meter claims in the suit that she experienced a pattern of discrimination from the officer in charge of K-9 training, Sgt. Anthony Phelps, that included him berating her, telling her in the third week of the 14-week program that he planned to fail her and assigning her a dog whose prospects for completing the program were in doubt, putting her own chance of success at risk.

According to the lawsuit, Phelps also blamed Van Meter when she complained about his treatment of her and “continually derided and belittled her” after she told him she suffered from anxiety and depression.

Capitol Police K-9 positions are highly coveted for their prestige, salary and benefits.

Van Meter, who claims she passed all tests and training modules before she was expelled from the program in Week 11, remains on the force with the rank of private first class. She declined to comment on the lawsuit through her attorney, who cited a policy that bars Capitol Police officers from speaking to the news media.

“Ms. Van Meter was belittled every step of the way as she sought to advance within the force,” said Les Alderman, a lawyer with Alderman, Devorsetz & Hora in Washington. “Her mistreatment points once again to the Capitol Police’s discrimination against women officers. This lawsuit will help to shed light on Capitol Police practices that have resulted in a predominantly male force and created impediments to female officers’ growth.”

Reached by email, Capitol Police communications director Eva Malecki said the force doesn’t comment on pending litigation.

Attempts to reach Phelps, who no longer works for the force, according to the complaint, were not successful.

Van Meter’s lawsuit comes amid a debate over what critics describe as persistent gender-based harassment and discrimination in congressional offices. The Capitol Police, the agency charged with protecting Capitol Hill and the thousands of people who work and visit there, has faced multiple allegations of sex discrimination and harassment in the past five years.

The department has a “history of being male-dominated and unwelcome to female officers” and required female officers to wear uniforms and body armor designed specifically for men until approximately the past 10 years, Van Meter’s lawsuit stated.