WASHINGTON — The Education Department’s Office for Civil Rights this past week closed a long-running discrimination case involving a transgender student and withdrew its earlier findings that the girl had suffered discrimination at school, a move that comes amid the Trump administration’s push to scale back civil rights investigations in public schools.

The agency communicated its decision in a letter this past week to lawyers representing the girl, an elementary-school student in Highland, Ohio. The letter provided no reason or legal justification for withdrawing its 2016 conclusion that the girl’s school wrongly barred her from the girls’ bathroom and failed to address the harassment she endured from classmates and teachers, who repeatedly called her by male pronouns and the male name she was given at birth.

Candice Jackson, acting head of the civil rights office, said the department closed the case because the student has filed a legal challenge against the school district, and the matter will be settled in court.

Officials withdrew the findings of discrimination, Jackson said, because those findings were based on guidance that directed schools to allow transgender students access to bathrooms matching their gender identity. The Trump administration rescinded that guidance in February.

Civil rights advocates see the closure of the Ohio case – and especially the unusual withdrawal of federal investigators’ legal conclusion – as a troubling sign of retreat from civil rights enforcement.

“This is so dangerous,” said Shannon Minter of the National Center for Lesbian Rights, which is representing the Ohio transgender student, identified only as Jane Doe, in a lawsuit against the school district. “They have just sent a message to schools that it’s open season on transgender students.”

The agency also this month closed a different long-running case involving a transgender student’s complaint about locker room access in Palatine, Ill., according to the American Civil Liberties Union, which represents the student in that case.