A bullet pierced a classroom window at Aiton Elementary School in the Lincoln Heights neighborhood of Northeast on Wednesday. No one was hurt, thanks to a fortuitously-timed field trip that meant students and teachers weren’t in the affected classroom during the incident.

Principal Malaika Golden said that “while the classroom was empty and no one was harmed, we approach situations like this with extreme caution,” in a letter to parents on Wednesday, first posted by FOX 5 senior assignment editor Allison Papson. The Department of General Services is working on fixing the window, Golden wrote.

A D.C. Public Schools spokesperson declined on Thursday to provide more details on the incident or make Golden available for comment, citing an ongoing police investigation.

Police told NBC 4 on Wednesday that the shooting resulted from a dispute between two people in different cars. One involved car also struck a utility pole in a nearby park, leaving more than three dozen nearby households without power, NBC 4 reported.

The incident comes just three months after a bullet broke a window in the lobby of Hendley Elementary in Southeast. That incident occurred at 4:20 p.m., while students and teachers were getting ready for a movie night event. Two students, age 9 and 10, and one teacher were in the room at the time, but no one was hurt.

Earlier this year, a man was fatally shot steps from Savoy Elementary in Southeast, and two men were shot less than 400 feet from Tubman Elementary in Columbia Heights.

Aiton Elementary last year enrolled 243 students, 98 percent of whom are black and the remaining 2 percent of whom are Hispanic, according to demographic data from D.C. Public Schools. Aiton had a 44 percent teacher turnover rate from 2015 to 2017, one of the highest in the city, a 2018 study from the DC State Board of Education. Aiton’s playground was listed as one of the 17 DCPS schools where the city found elevated levels of lead, according to a report released last week.

Violence near schools has long been an issue in D.C. An analysis from Guns & America (which is owned by DCist’s parent company WAMU) this June found that at least 84 D.C. schools experienced at least one gunshot within a 1,000-foot radius during the 2016-2017 school year alone—five school campuses each experienced at least 10 shootings. A D.C. elementary school principal said at the time that students had become “desensitized” to threats of violence after numerous lockdowns in a single school year.

Last month, Mayor Muriel Bowser announced a suite of initiatives to improve school safety, including an app designed to help students send emergency alerts and a partnership with local businesses and organizations to accompany students on their commutes. At-large D.C. Council member David Grosso also introduced a bill this summer that would establish a citywide Office of Safe Passage to help students get to school safely.