Loch Raven High School was placed on lockdown around 11:45 a.m. after a student told the officer on campus they saw a gun in a freshman's backpack.
According to Baltimore County Police, a School Resource Officer approached the student, who ran away.
The lockdown was initiated after the SRO lost sight of the student.
"I was in my history class and they just called for a like a severe lockdown with the school so they turned off the lights and everything and we had to be really quiet," Senior ELNesha Alstonstreet said.
"I was in the cafeteria and then they were like we're going on alert lockdown and everyone who came in were like the officers were chasing somebody," Senior Jasmine Schnitker said.
Students said the freshman brought the gun to school to get even after he lost a fight yesterday.
Parents anxiously waited on Cromwell Bridge and Lock Raven Roads to get to their children at the school.
"Today my daughter woke up and said she had a nightmare and that she was shot and I was like well it was probably just a bad dream after yesterday's incident and I just prayed and we rebuked it and I sent her to school," Parent April Ross said.
— Cassie Carlisle (@ReporterCassie) February 15, 2018
The student was arrested. Police say the student will remain in custody pending charges.
The school is no longer on lockdown and will be open Friday. Kevin Kamenetz said it's up to the school system and police department as to whether or not there will be a higher police presence tomorrow.