Kylo Lim, a senior, was arrested on suspicion of felony possession of a gun on school grounds and misdemeanor possession of a concealed handgun, according to the Santa Rosa Police Department.
Santa Rosa police Sgt. Chris Mahurin described the gun as a Glock 17 semiautomatic that was registered to a family member, whom investigators will interview.
“It was not mom and dad,” the sergeant said.
With few exceptions, it is illegal in California for a person under 21 to own or possess a handgun.
The arrest happened just after 10 a.m. after officers were notified about a possibly armed student on campus.
The student was identified and removed from class. Investigators searched his backpack and found the gun, police said.
Police had no previous history with Lim. “He was fully cooperative,” Mahurin said.
In a letter to parents, Principal Adam Paulson said the student had the gun for “personal safety and not to threaten anyone on campus.”
“There is no evidence of anyone besides this individual involved in this case and no further threat to school safety,” Paulson wrote.
Mahurin confirmed there was no indication that the teen intended to harm classmates but added police are still investigating why Lim had the gun and brought it to school.
Paulson described the incident as a “very unusual occurrence” but stressed weapons of any kind are not allowed at school.
The arrest was among three incidents involving reported threats to Santa Rosa schools on Thursday and Friday, police said.
About 9:40 a.m. Thursday, officers went to North Valley School in northwest Santa Rosa regarding a 14-year-old boy making threats about injuring classmates and sending bombs to the school.
Police searched his belongings after removing him from class but did not find any weapons or other items illegal to possess. His home was searched, but no explosive devices were found.
Officers arrested the boy on suspicion of making criminal threats, and he was booked into the Sonoma County Juvenile Justice Center.
Around 8:45 a.m. Friday, police went to Santa Rosa High School after a parent notified them about a suspicious post on Snapchat.
It was a question asking whether anyone knew about a possible shooting expected to happen Friday at Santa Rosa High School.
Officers worked with school administrators and interviewed several students before determining there was no danger to students or school staff.
Two officers remained on campus until 1:30 p.m. Friday. Mahurin said investigators haven’t identified the post’s origin.
You can reach Staff Writer Colin Atagi at email@example.com. On Twitter @colin_atagi.