A Maryland school district has removed top staff from a high school where investigators found violations of grading and graduation certification procedures.

The Washington Post reports the principal, assistant principal and three other employees of DuVal High have been removed. Prince George’s County officials announced the changes Jan. 22, but declined to provide details.

DuVal was praised last year for having a graduation rate above 90 percent. But a report sampling students with late grade changes in 2016 and 2017 found more than a quarter of that group either didn’t qualify to graduate or lacked graduation eligibility documentation. The report found the school ran an unofficial credit recovery program to make up for failing grades.

The district will appear before the State Board of Education next week to address the report.