The Department of Education opened a civil rights investigation into Portland Public Schools following a complaint that alleged the district engaged in unlawful racial discrimination by creating a Center for Black Student Excellence.

The inquiry, announced Tuesday, stems from a December complaint filed by Defending Education, a conservative national nonprofit group that challenges diversity, equity, and inclusion initiatives. The Washington Examiner first reported on the filing at the time, detailing allegations that the district was steering millions of taxpayer dollars into a race-focused program in violation of Title VI of the Civil Rights Act and the Constitution’s equal protection clause.