Penn Hills School District officials report that a student who brought a loaded gun into the high school last Thursday has been removed from the school.

The security guard who failed to follow metal detector procedures at the main entrance has been removed from the district.

Officials did not provide names of the student or security guard but said the student would be disciplined according to Act 26, a state law that requires expulsion for at least one year for any student who possesses a weapon on school property, at a school function or going to or from school.

Police Chief Howard Burton confirmed that a criminal investigation is under way to see whether charges will be filed. The gun, a .25-caliber semiautomatic pistol, does not appear to be a stolen weapon, he said.

The student is subject to two types of violations: of the Uniform Firearms Act and of bringing a weapon onto school property. Chief Burton did not know whether the student had a criminal record.

The school district reported that through a "security breach," the student brought the concealed gun into the school. The gun fell from the student's pants in the hallway. A teacher recovered the gun and gave it to school administrators, who called police. The student ran out of the building.

The student was later located.

School officials said they did not know why the student brought the gun into the school.

The incident came under discussion Saturday at a town hall meeting sponsored by the Penn Hills NAACP at Lincoln Park Community Center. The meeting had been scheduled at least two weeks earlier to discuss bullying in Penn Hills schools.

At that meeting, school board members Carolyn Faggioli and Erin Vecchio questioned the district's handling of the gun incident, including whether a lockdown should have been called and whether additional security measures are needed. Both board members have children who attend the high school.

District administrators make the determination to call a lockdown, said spokeswoman Teresita Kolenchak.

"An assessment was made by the administration that a lockdown was not necessary since the administration had the weapon, the student was no longer in the building and the situation was contained," she said. "We did not want to cause undue panic among the student population."

Staff, students and parents were provided with information about the incident through the Web site www.phsd.k12.pa.us, said Ms. Kolenchak. The district did not directly contact students or parents.

Chief Burton said the police department notifies schools if there is an incident outside a building that would require a lockdown. He said he didn't know of any police officer offering advice to district administrators concerning a lockdown.

In a phone interview, Penn Hills PTA Council President Meryl Thomas expressed concerns over security procedures at the high school and said PTA officers had often brought this complaint to administrators.