Police were investigating reports that a student brought a gun to La Jolla High School on Thursday, but found no gun and no credible threat, the district said.
In a letter sent out to parents, principal Chuck Podhorsky said San Diego Unified School District police were actively investigating a threat to the campus that was reported by a student.
According to Maureen Magee with the district, no gun was found and the threat was found to be non-credible. Magee said that police came to the campus out of an abundance of caution.
Podhorsky said that school police will have extra resources at the school Friday morning for a lockdown drill.
"I want to assure you that we take the safety of everyone on our campus seriously and investigate each one," Podhorksy said in the letter.
Podhorsky ended the letter by asking parents to talk to their children about the consequences of making comments, including on social media, that could be perceived as a threat.
In the weeks following the deadly Parkland, Florida high school shooting, law enforcement agencies in San Diego have made several arrests regarding threats.
Earlier Thursday in Chula Vista, a 10th-grade student at Olympian High School was arrested Thursday after she admitted to police that she made a shooting threat in jest on social media.
On Monday, March 5, a teenager was booked into juvenile hall, accused of making criminal threats on social media aimed at Canyon Crest Academy. The school is in the San Dieguito Union High School District.
A Borrego Springs High School student was suspended on March 1 for threatening to blow up the school. County prosecutors determined no charges would be filed in the case.
A 14-year-old West Hills High School freshman was arrested on Feb. 28 for posting a photo of an AR-15 rifle made out of Legos on Instagram with a caption that read, "Don't come to school tomorrow."
On Feb. 27, a Westview High School student was arrested after he was overheard telling classmates to stay home, SDPD investigators said. The unidentified teenager was booked into juvenile hall.
On Feb. 26, a teenager, 17, who was a former student of Torrey Pines High School was arrested and accused of threatening to conduct a shooting at the school. It was the second arrest involving the school. In an unrelated case, a 14-year-old freshman was booked into juvenile hall for making verbal and written threats to harm others, police said.
San Diego police are looking for leads into who tagged various buildings on the campus of Rancho Bernardo High School. The messages discovered by staff on Monday, Feb. 26 referenced the deadly Parkland shooting.
On Feb. 23, an 18-year-old El Centro man was charged with making criminal threats against students and teachers at Imperial High School in Imperial County.
On Feb. 21, San Diego police were made aware of messages on social media threatening a shooting at two Clairemont schools - Madison High School and Creative Performing Media Arts Middle School. The next day, a second message was posted that added San Diego High School and School of Creative and Performing Arts to the list of possible targets. Officials with San Diego Unified School District said the threats were believed to be connected to a middle school student.
On Feb. 20, a message scrolled on the wall of a girls' bathroom prompted an increase in security at High Tech High in Point Loma. That same week, additional security was in place at San Marcos High School for a separate threat and at Scripps Ranch High School following a student's comment perceived to be threatening to public safety.