A tense few days at Pickerington High School North last week included three separate incidents -- one involving a lockdown and each of the other two ending with the removal of a student from a building.

District officials reportedly had planned to hold public forum for students and parents to discuss school safety and the incidents Feb. 27.

North was put on "lockdown" -- meaning all doors are locked and students are to remain in their classrooms -- about 8:30 a.m. Feb. 22 after a student told school officials she believed a person who wasn't permitted to be at school was inside the building.

According to Fairfield County Sheriff Lt. Marc Churchill, a school resource officer from the sheriff's office immediately began to search the building after the lockdown was declared, and at least three other sheriff's office officials also came to the school.

The alleged intruder wasn't found, no one was hurt and the school was deemed safe. But according to Churchill, the lockdown, which was the third incident in three consecutive days, might have been one too many for parents and students.

"The decision was made to release the lockdown," Churchill said, "(and) that presented a whole different problem.

He said students used social media to post information about the lockdown and numerous parents came to the school with the intention of picking up their children.

"I would say that by noon, over 500 students had left the building, signed out of school," Churchill said.

Pickerington schools public relations director David Ball said the lock down lasted about 35 minutes

He said about half of the approximately 1,600 students North left after the lockdown ended.

Ball said those who left the building, including those signed out by parents, would be assessed an unexcused absence for the day.

"We do ask parents not to come to schools to pick up their kids because it kind of creates additional chaos and security issues at the building," he said.

The lockdown followed separate incidents the two previous days at North.

In each case, no students were harmed and no weapons were found in the building.

A male student was removed from the school Feb. 20 after allegedly bringing a single, .22-caliber bullet to school and showing it to students "at numerous locations throughout the school," Superintendent Chris Briggs wrote in an email to parents.

Briggs said North administrators "immediately located the student, performed a search of his belongings and located the bullet."

The Fairfield County Sheriff's Office opened an investigation into the matter and Briggs said the student would face "appropriate discipline."

"This sort of behavior is never appropriate, but given the heightened attention currently placed on gun violence in our schools, many of our students are understandably upset," Briggs wrote in the email.

The following day, Feb. 21, another male student was removed from North after allegedly bringing an ammunition magazine for a pellet gun, which Briggs described in an email to parents as "a very low-powered replica weapon that typically shoots things like BBs made of plastic or biodegradable resin."

District officials said North administrators were alerted about the magazine by a student who said the alleged culprit had displayed it a week earlier on a school bus. The suspect student reportedly was called to the school office and the clip was confiscated.

"While we cannot discuss specific student discipline, we will say this student was removed from school," Briggs said in an email to parents. "The student did not possess an actual weapon.

"While some would consider (pellet gun) replicas to be toys, possession of lookalike weapons is a serious violation of our student code and is subject to discipline."

Later Feb. 21, Briggs sent another email to parents to quash a rumor circulating among students and on social media that a student involved in an "incident" at North earlier in the week might have a "hit list."

"We take all such concerns for student safety seriously, so when we became aware of this rumor, we immediately investigated and determined there was no such list," Briggs' email stated.

Briggs' emails also stated student safety is the district's "primary responsibility, and that a public school is still one of the safest places your children can be."

He stressed district and North officials work with school resource officers and local law enforcement agencies to maintain security, and secure vestibules, lockdown/ intruder training, and security cameras had been installed and implemented at all district buildings in recent years.

As for the Feb. 22 lockdown, Churchill said it was erroneously reported to school officials that a student that had been expelled prior to last week was in the building.

"There was no threat at the school," Churchill said. "(The expelled student) was home in bed.

"The staff at Pickerington North do an absolutely fabulous job of maintaining student security."

Churchill said the sheriff's office has "absolutely no intent to file criminal charges" against the student who reported the intruder.

District officials said additional law enforcement officers were assigned to North throughout last week, and urged students and parents to continue to speak up as security concerns arise.

"We certainly always encourage students and parents who believe they have information to bring it to our attention, and we've seen the benefits of that a couple times this week," Ball said.