ALTAMONTE SPRINGS, Fla. — A student who brought what appeared to be gun to Lake Brantley High School on the two-year anniversary of the Parkland tragedy prompted a lockdown and a large law enforcement response at the school Friday.

A "code red" was issued on campus just after 8 a.m. and was downgraded to a "code yellow" at about 10 a.m.

No one was hurt, and a juvenile was detained. Police determined the weapon was a BB gun.

According to Michelle Sosa, a spokesperson for the Altamonte Springs Police Department, law enforcement was investigating a social media video that circulated around campus that showed what appeared to be a gun and a scared girl.

"Unfortunately, a student has been apprehended with a weapon on campus. Please be assured all students and staff are safe," she said in a second news release.

"The student is in custody. Also we have located the weapon. At this time, (we're) trying to process that weapon to confirm if it was a fire arm our a BB gun," Sosa said.

After the code yellow, parents anxiously waited to pick up their children after the incident.

"So many things went through my head," parent Karen Hennessey said. "I only have one of her, and what are these kids thinking? Why would they bring a gun to school?"

Phoebe Nicholson took cover under a desk. She said she wasn’t quite sure what was happening but knew to take it seriously.

"I didn’t know what was going on, but I knew not to freak out, because freaking out makes everything worse," Nicholson said. "In order to stay calm, (I) kept everyone around me calm."

Three juveniles were detained: the girl seen in the video, the person with the BB gun, and the student who recorded the video, which the principal thinks was recorded on campus.

One juvenile was in police custody; their identity hasn't been released.

"I’m gonna tell (my son), hug him, say, 'Look, whatever has happened in the past, forget about it. Life is too short," Lake Brantley parent Deshawn Eason said.

A Volusia County Schools spokesperson said around 1,000 students were absent from Mainland High on Friday -- there are 1,834 students enrolled at the school.

Lake Brantley High Principal Brian Blasewitz released a statement on the incident Friday afternoon, saying, in part:

"The thing that I am most proud of is the fact that all of the processes and trainings we have in placed worked perfectly today.  A situation like this reinforces how important it is for you to talk to your kids about our anonymous tip hotlines that we have available.  Whether it is the Speak Out Hotline, or P3 campus app, or Fortify Florida, encouraging your students to “See Something, Say Something” is crucial to keeping our campus safe.  These incidents are not a joke ..."

At Mainland High School in Daytona Beach, a person was taken into custody after posting a shooting threat on Thursday.

Friday — Valentine's Day — marked two years since the deadly shooting at Marjory Stoneman Douglas High School in Parkland, Florida that left 17 people dead.