The attendance records of some students at Roosevelt High have been altered in recent months to erase absences, several teachers allege — a breach that could allow chronically absent seniors to cross the graduation stage this spring.

School system officials Friday said they have opened an investigation into the alleged wrongdoing at the Northwest Washington school. The disclosure emerges just four months after a probe concluded that 1 of every 3 graduates last year from the District’s public schools missed too many classes or improperly took makeup classes, undermining the validity of hundreds of diplomas.

D.C. Public Schools “takes any accusations of tampering with data very seriously. We were made aware of allegations at Roosevelt through the proper protocols and launched an investigation into the matter,” school officials said in a statement. “Once the investigation concludes, we will review the results and take the appropriate action.”

The D.C. school system acknowledged the existence of the Roosevelt attendance investigation in response to evidence presented by The Washington Post.

City policy states that students who accrue more than 30 unexcused absences in a class during the school year should fail that class. Several Roosevelt teachers say records were changed to ensure that some seniors remained below the threshold. The teachers requested anonymity, they said, because they feared retaliation if they spoke publicly.

The Roosevelt teachers said they discovered that attendance records for at least a dozen seniors had been changed. Original records showed that the seniors earned failing grades during the first quarter because they missed too many classes. But teachers say altered attendance records now indicate that some of the students did not miss a single class during the first quarter, reducing the students’ absences over the entire year to fewer than 30.

Attendance and grading records obtained by The Post indicate that some students who accrued dozens of absences in the second and third quarters are now listed as having zero absences in the first quarter. The staff members, who are familiar with the students’ academic performance, said the first-quarter attendance data does not accurately reflect how often the teenagers showed up to class.

“It’s pretty clear that someone has changed the attendance records,” one teacher said. “It’s not just one student.”

Elizabeth Davis, president of the Washington Teachers’ Union, said her office has fielded complaints from teachers at Roosevelt about the alleged record tampering. She said she is aware of at least one teacher alerting the D.C. school system’s central offices last week.

Davis said pressure to have high test scores and lofty graduation rates led to the alleged wrongdoing. She said IMPACT — the school system’s controversial evaluation system that ties teachers’ and school leaders’ bonuses and job security to their annual evaluation scores — has been at the root of the problems.

According to Davis, the union continues to receive complaints from teachers across the city that schools are not following policies.

“This growing environment of fear and mistrust has never been addressed and continues to be a disservice to students and teachers,” Davis wrote in an email.

The city-commissioned investigation that was released in January revealed that schools have long ignored the District’s attendance and graduation policies. In the wake of that review, administrators tightened enforcement of attendance rules.

But many students argued that it was unfair to ramp up enforcement of the rules midyear and said the city should give them a reprieve until next year.

Roosevelt’s graduation rate in 2017 was 60 percent, below the 73 percent citywide average. City data released last month showed that 29 percent of the school’s 207 seniors are on track to graduate this year. Thirty-three percent are “moderately off-track,” meaning they can still earn enough credits to graduate. Nearly 38 percent of students who started at Roosevelt as freshmen in 2014 and were considered part of the Class of 2018 have withdrawn from the school.

D.C. Council member Robert C. White Jr. (D-At Large) called on the council to pass emergency legislation that would help seniors who cannot graduate because of poor attendance. He said that only students’ second-semester attendance should count toward their final grades for the 2017-2018 academic year.

“When students began this school year, they were operating under one attendance practice,” White said in a statement. “But that practice changed midyear, so students who have mastered their subjects and believed they were on track for graduation or promotion are now finding themselves paying the price for a [school system] mistake.”