Keys deputies went floor-by-floor, classroom-to-classroom clearing Coral Shores High School Monday morning responding to reports of an armed person on the Tavernier campus.
They didn't find anybody and theorize the report was due to a child seeing a person with an umbrella and mistaking the item for a rifle.
Principal Blake Fry said after the lockdown was lifted around 10 a.m. that at no time was anyone in danger.
The Monroe Sheriff's Office received a single report at 7:48 a.m. about the alleged armed person, agency spokeswoman Deputy Becky Herrin said. The school was locked down as police checked out the campus.
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Sheriff's Office Capt. Corey Bryan said a mother who dropped her teen off at the school called police when her other child in the back seat of her car reported seeing a man with a gun. That child likely saw an umbrella and thought it was a gun, Bryan said.
At 9 a.m., deputies were still sweeping the building but found nothing, Herrin said. Parents were given the option of taking their children home after the all-clear was given, but Fry reiterated that authorities do not believe there was any danger.
"We'll chalk this one up as a drill," he said.
Bryan said there were no arrests, and he does not anticipate any.
"Nobody was arrested because there was nobody," Bryan said to parents outside the school Monday morning.
Bryan and Fry praised school staff, responding law enforcement and students.
"All the kids did really well. School staff handled it very, very well," Bryan said. "It's one of those situations where everybody was prepared."
While worried parents waited outside the school, their children were texting them, barricaded inside their classrooms.
"I just dropped my daughter off, and as I was pulling out, I got a text, 'mom the school is on lockdown and I don't know what to do,'" said parent Angie Liberty.
Bryan O'Berry's son Chris spent the morning inside a closet.
"They're all in a closet and just want to get out," O'Berry said.
Still, most parents praised Bryan and his deputies. They gave an ovation to the Sheriff's Office when the all-clear was given. With frequent mass shootings nationwide, most agreed that the way school and law enforcement responded was necessary.
That doesn't sooth the sting, however, of parents knowing the often violent world in which their children are growing up.
"With the amount of stress these kids deal with these days, this is the last thing they need," said Liberty.