A 16-year-old ran into a St. Paul school on Wednesday with a loaded, stolen gun in his pocket before quickly leaving and being arrested in the neighborhood, according to a charge filed against the teen Thursday.

Humboldt High School and Open World Learning, which share a building complex on the West Side, went into a short lockdown, according to letters sent home from the principals. School was out for the day, though the Extended Day for Learning program was in session at both schools; 280 students are enrolled in the program.

At 3:30 p.m. Wednesday, school staff told a St. Paul police school resource officer at Humboldt that a former student was walking toward the school.

The officer, who knew the teen had felony warrants and was a theft suspect, yelled for him to put up his hands. He initially did, but then suddenly fled, according to the juvenile petition filed in Ramsey County District Court, charging him with possession of a dangerous weapon on school property.

He ran to the school’s locked side doors, was let in by a group of students, ran through the building and out the side “within seconds,” Humboldt Principal Michael Sodomka and Open World Learning Principal David Gundale wrote to parents.

The teen ran through nearby yards, and a resident detained him until officers arrived and arrested him.

Police found a handgun with a round in the chamber in the teen’s front pocket, the petition said. It had been stolen from Savage.