Grossmont High School in San Diego’s East County was placed on a three-hour lockdown Thursday due to a "possible threat" ultimately deemed unsubstantiated by officials.
Catherine Martin, a public information officer for the Grossmont Unified High School District (GUHSD), said the campus was placed in “secure” mode at around 8:45 a.m. due to “police-related activity.” She posted a message on Twitter saying all students were safe and were being kept inside classrooms. "Secure Campus" means the doors to classrooms are locked, with instruction continuing.
Officers with the El Cajon Police Department (ECPD) were called to the school. Police said the lockdown was a precaution.
At around 9:45 a.m., Martin tweeted that police were “investigating a possible threat” to the high school.
“Students are safe/secure,” she added.
Martin said the ECPD had been able to confirm “that no students at Grossmont High School were directly threatened.”
NBC 7 crews saw a large police presence surrounding the campus.
Concerned parents had gathered at the entrance to the school, waiting to hear from their children and officials. One mother told NBC 7 she had received one text from her son and a text message from the school district but heard nothing else for several hours.
At around 10:20 a.m., Martin tweeted that U.S. Customs and Border Protection (CBP) officers were also on campus, only there to help El Cajon police with K-9 searches as the dogs sniffed for weapons.
About a half-hour later, with the school still on lockdown, Martin posted another message on social media, saying officers were still searching the roughly 20 buildings on the 66-acre campus.
Martin also said that as campus buildings were cleared, students were being allowed out of classrooms to use the restrooms. She said classrooms are equipped with "crisis buckets," which include supplies like snacks and water.
By 12 p.m., Martin said the lockdown had been lifted, as police were "unable to substantiate any threat to students."
Students were let out of their classrooms for lunch; classes would resume for the rest of the day after that, with normal release for students at 1:48 p.m. and 2:48 p.m.
ECPD Lt. Rob Ransweiler said Thursday's ordeal began when a student on campus saw what she thought was another student with a weapon in his backpack. The student reported the incident to a campus resource officer who then called for the campus lockdown and for backup from the ECPD.
"A methodical search was done of the entire campus to ensure that none of the students were in danger. No weapons were recovered as a result of the search," Ransweiler explained.
The lieutenant said other agencies, including the La Mesa Police Department and San Diego County Sheriff's Department, also helped search the large campus to resolve the matter as soon as possible. This meant going from classroom to classroom and patting down some students.
As for the CBP K-9s, Ransweiler echoed Martin's statement on why the federal agency had been called to the campus.
"The dogs that showed up on scene -- all dogs, not just CBP -- were here because they are article search dogs trained specifically to search for firearms. They have that specialty and it was the only reason they were on campus today," he added.
"We take student safety very seriously," Martin told reporters following the lifting of the lockdown. "It's a time in which we want to ensure our parents with the maximum amount of information when a school does have a lockdown and to let them know that their kid's safety is our highest priority."
The incident was jarring for some parents, including Tanisha Turner, whose son attends Grossmont High School.
“I feel relieved. I feel a lot of pressure is off of my heart and off of my chest now,” she told NBC 7 after the lockdown was lifted.
Her son's phone was broken, so Turner had no way of communicating with him.
"This morning I was a wreck because I didn’t know what was going on with my son," she explained. "You hear about all of these different shootings going on across the world and you don’t know – you don’t know what to think."
Turner planned to pull her son out of school early for the day and was waiting to be reunited with him.
"I'm going to take him home, just to see how he feels, to see where his mind is at," she added. "And talk about the incident with him, and maybe we can try to figure out a plan if this happens again."
Grossmont High School is located at 1100 Murray Dr. in El Cajon and serves approximately 2,000 students in grades nine to 12.
No other information was released regarding the investigation.