The school was locked down along with National Cathedral School and Beauvoir School for more than an hour Wednesday morning after someone reported spotting a person with a gun in the woods near the school.
Police searched the area for the person and weapon and eventually found a "long gun" in the back of a St. Albans student's vehicle parked on campus. A school official told News4 it was a BB gun.
Police said they identified two students who were believed to be in the vehicle. One of the students was seen being taken out of National Cathedral School's Hearst Hall in handcuffs at about 9:15 a.m. The student, who was wearing a white shirt and tie, was placed in a squad car and taken away.
A juvenile was charged with illegal possession of a BB gun. The 18-year-old driver of the vehicle was charged with illegal transportation of a BB gun. It's illegal for a minor to possess a BB gun in D.C.
No injuries were reported. Police took the school off lockdown at 9:30 a.m. and said there is no longer a threat to the school or area around it.
The police investigation continues.