Upper Dublin High School went on lockdown just before 9 a.m. Monday after what police call a "suspicious incident."
The lockdown was very brief and police tell NBC10 it was initiated after school security saw four students in the hall with what looked like a long gun.
Investigators say the suspected gun turned out to be a long umbrella.
"All the kids were scared. All the kids in there were crying and they just want their parents," said parent Heather Saraceni.
The four male students were questioned by police.
Parents were emotional as they showed up after hearing about the lockdown. Some heard the news after receiving a text message from their kids inside the school.
"I just took off from work, and I said I'm coming there and I'm coming to get you right now," said Saraceni.
"I got a text message from my son saying that the high school was on lockdown, so I decided I better get over here and figure out what's going on," said parent Tony Davis.
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Upper Dublin High School is located at 801 Loch Alsh Avenue in Fort Washington.
This lockdown scare comes amid nationwide concerns over school security, on the first school day since a gunman shot and killed 26 children and adults at Sandy Hook Elementary School in Newtown, Conn.