(WJLA) - Parents ran to the school - only to be turned away; they called - only to receive no answer.
"They said it was a code red," said Northwest High School guardian, Maurice Staples.
The school in Montgomery County went on lockdown with 2,000 students. Mary Million's five-year-old is among the youngest enrolled in Northwest's preschool program.
"You feel bad and scared for your child -- especially when there is no way to go in to help," she said.
Multiple sources tell ABC 7 that investigators, including the FBI, found an account on a popular social media site that claimed responsibility for all three prank calls threatening violence.
"It's not funny at all, it's very serious to take everyone's time and put people in that emotional state...It's not fun at all," said parent Janet Forster.
Students say they were even hiding under desks in fear.
Freshman Nusheena Parvizi had barely overcome last week's bomb scare, which literally sent students running for the hills:
"I wasn't taking an AP exam, but my friends that were said, 'Oh my god, how am I supposed to continue?' Most of them had studied all night...they just want to take their test and be done with it."
"Whoever is doing this needs to be taught a good lesson, because it's not funny at all. This is very serious," said parent Trish Poulos.