O.D. Wyatt High School in Fort Worth was under a lockdown Monday, the first day of classes, after a photograph of a student with a firearm on campus was reported, according to Fort Worth ISD. 

Five people, including the student who took the photograph, have been arrested, Fort Worth ISD said in a statement. 

Students were being released from the school as of 4:14 p.m., Wood said.

A student called her parent and told them that someone had a gun at school, Fort Worth Police spokesperson Cynthia Wood said. The parent then called the police, and officers were dispatched shortly after, Wood said.

Fort Worth ISD said students and staff are safe, and the lockdown was initiated as a safety precaution while Fort Worth police continue their investigation.

The police department and school district are working together and will provide additional information as the investigation continues, according to the statement. “The safety and well-being of our students and staff remain our highest priority,” the statement reads. 

Monday marked Fort Worth ISD’s first full day under state intervention, a change that caused parent pushback and hundreds of teacher resignations. The Texas Education Agency first began the intervention in March, appointing a new superintendent and board later that month.

Many other school districts, such as Dallas ISD, Prosper ISD and Plano ISD, begin school Tuesday.