A Tierrasanta teacher arrested for having a loaded gun on campus once told students that he had the gun to protect the school according to one student.
Farb Middle School teacher Ned Walker, 41, was arrested Monday in the school's parking lot for having a .380 loaded semi-automatic handgun with a 7-round magazine as well as a 2.5 inch locking blade knife in his car.
After the school's staff told the vice principal that Walker may be storing ammunition on campus, she contacted school police, according to district spokesperson Jack Brandais.
“A search of the two cabinets revealed no ammunition or weapons however during a search of the parking lot and the suspect’s car in the parking lot it was determined he was in possession of a loaded firearm,” said San Diego Unified District Chief of Police Rueben Littlejohn.
When he was first questioned by police, Walker denied possessing the gun officials said.
Officers say they found a gun and wallet holster in the teacher's front right pocket during a pat-down.
“This employee has somewhat of an infatuation with guns and brought the weapon to the school to protect himself in the event of a violent intruder,” Littlejohn said.
Walker faces a felony charge of possession of a firearm on school property. He's also facing charges of possession of a knife with a locking blade.
Police are currently investigating the incident to determine how long he was carrying the gun on school grounds.
San Diego Unified School District has a zero tolerance policy involving weapons, controlled substances or violence.
“With the exception of police, no one should be carrying a gun on school grounds,” Littlejohn said.
A group of Ned Walker's former students said they knew the teacher had a weapon.
Walker’s former student Astin Martin told NBC 7 San Diego, "We all knew. We all knew that he had a gun.”
“He just said it was for protection for us. We didn't really think he'd doing anything with it, he's a good teacher," Martin said.
When asked how it became common knowledge on campus, Martin said Walker revealed that he had the gun to his students at the beginning of the year.
“'I just have it for protection reasons in case something happened at the school,'” Astin recalled the teacher telling the class. “And we're like 'oh [ok]', and he's like 'yeah', and it was just pretty much, we knew about it."
Martin told NBC 7 San Diego the idea of a teacher having a gun on campus didn't bother the class.
"It made us feel extra protected," he said.
Parents feel differently.
Janine Lint believes it’s completely unacceptable regardless of the reason.
"I understand that there's a point where we all want to protect the kids, but I think that's up to the school board to place security at schools. I don't think it's the teacher's responsibility to play security guard," Lint said.
Parent Jong Riojas believes there are other ways Walker could offer a feeling of security to students.
"No, it's not right. It's not safe for kids. He can do other things, you know, come in the school, talk to the kids, those things are safe, but gun stuff, that's very danger[ous], you know," Riojas said.
Walker was booked into San Diego Central Jail just after noon on Monday, the Sheriff's Department website showed. 
Brandais said Walker has been with the San Diego Unified School District since November 2003 and has been teaching seventh and eighth grade English since 2003.
Interim principal Courtney Rizzo issued a statement to parents on the school's website.
"At Farb Middle School, our first priority is to provide a safe learning environment for our children," read a statement on the school's website. "We also believe in keeping our school community informed about incidents that occur on campus affect our children."
The incident occurred just days after a Poway middle school student was taken in custody in an alleged school shooting plot. An email to a school administrator referenced 3,000 rounds of ammunition as well as numerous firearms in the plot.
Read: Poway Teacher Named in Alleged School Shooting Plot
One parent says the school should have been better about informing parents and students of the teacher sooner.
"My eighth-grade daughter was unaware that anything had happened until she got home from school at 5:30 p.m.," Farb Middle School parent Heather Fitzner Wooldridge wrote to NBC 7 San Diego. "Parents are outraged that more information is not being given."
"I understand that you may want more information but due to the fact that this is an active investigation, we are not at liberty to release any additional information or details," Rizzo wrote in the school's statement. "Our focus is to continue to ensure that our students are safe, the learning process goes on as usual, and we work with the proper authorities."
Walker currently teaches seventh and eighth grade English at the middle school but once taught at Hamilton Elementary School.
He has been placed on administrative leave pending the investigation.