Upper Darby Police Superintendent Michael Chitwood revealed the student's history during a news conference Wednesday morning announcing his latest arrest on weapons, drug and assault charges.
"This 12th grader, back when the pope visited, he threatened to kill the pope," Chitwood said. "He threatened to kill the pope. He got locked up for terroristic threats and harassment. He's back in school.... This kid should've been put away somewhere for evaluation. Now he's trying to walk into the school with a gun."
The student is one of two students arrested Wednesday morning at Upper Darby High School on Lansdowne Avenue in Drexel Hill, Pa.
School officials say they got advance word that a 12th grader was bringing some kind of weapon to school.
Security personnel and Upper Darby Township Police were able to meet that student's bus as it arrived Wednesday morning.
Upper Darby Police to charge two High Schoolers alleging one had gun & tried to pass to other during a scuffle with police.— John Rawlins (@JRawlins6abc) February 1, 2017
The student scuffled briefly with an Upper Darby police officer as he tried to escape, police said.
The officer suffered a cut on his head before the student was subdued and handcuffed.
At some point, officials say, the student tried to hand a black box containing a loaded handgun to a fellow student, identified as a 17-year-old 11th grader, who police say also became physically aggressive.
Thanks to the admin and police on scene, a weapon was confiscated today on UDHS grounds. No one injured. 2 in custody. News conference at 11— Upper Darby Police (@UDPolice) February 1, 2017
Both were handcuffed and led into the school's security office, where police opened the box.
Inside, they found a loaded 9mm handgun, extra ammunition and several vials containing marijuana. Both students were placed under arrest.
Chitwood said both are expected to be charged as adults with weapons and drug offenses.
UDHS: Everyone at the UDHS is safe and there was never a direct threat to any student on the grounds. Police continue to be present in HS— Upper Darby Police (@UDPolice) February 1, 2017
The 12th grader is also facing an aggravated assault charge in connection with the scuffle that injured the police officer.
School officials stressed Wednesday morning's incident was handled and contained entirely outside the high school itself, and that at no time were any other students in danger.