By Joe Holden

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UPPER DARBY TOWNSHIP, Pa. (CBS) — Distraught parents in contact with their children by cellphone, many of them rushed to Upper Darby High School after hearing the school was locked down for reports of a suspicious man with a gun.

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“Immediately when I heard it, I, my heart started pounding,” parent Dekontee Mau said.

Police from a half dozen neighboring departments flooded the campus where 3,700 students are educated daily. Parents say they struggled to get information on what was going on, and confronted police.

Around 10:15 a.m., police and school officials lifted the lockdown.

“We received information from a personal care assistant in the hallway who witnessed what he believed to be a gun dropping out of a backpack of a student,” acting superintendent Dan McGarry said.

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After a classroom-by-classroom search, detectives located a 16-year-old boy who they say brought the replica gun to school.

“Now when you look at the gun, it’s a plastic gun, it looks as real as any gun I’ve ever seen,” superintendent Michael Chitwood said.

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“I think it was stupidity,” Chitwood said. “No, he had no intention of hurting anybody, preliminary.”

The student has not been identified but officials say charges are pending against him.

The district was initially going to resume a regular school day, but later changed their minds due in part because of the amount of people around the high school.

Some parents were taking their children home regardless.

“I can’t imagine leaving her here, and finding out another thing is going to happen,” Mau said. “I’m just afraid something else is going to happen.”

Upper Darby High School dismissed students early after a student was placed in custody for sparking a lockdown due to reports of a gun on campus Thursday morning.

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“I’m very thankful to the Upper Darby Police Department. My child is safe so that’s what’s important,” said parent Mack Taylor. “I wish there would have been better communication with the school district, but you know, this isn’t what we usually see in Upper Darby so it happens.”

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Classes will resume as scheduled on Friday.