ROCKLIN (CBS13) – A Rocklin High School senior has been arrested for bringing a gun to school. It happened on Friday afternoon.

Following a motto at Rocklin High “see something, sense something, say something and do something,” a student reported the gun to school administrators.

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“He purposefully brought a firearm to school,” said Sgt. Greg Jensen with the Rocklin Police Department.

Jensen said a student reported seeing a classmate not only bring a gun to school but pull it out in the middle of class.

“He pulled it out of his backpack in a position where people could see it and then he put it back inside of his backpack,” Jensen said.

Police responded but, the 18-year-old was already back at home. Jacob Clark was arrested after police found the handgun there and he admitted he had brought it to school.

Just last week, a traffic stop on a Stockton High School campus led officers to a gun in the car and a bullet magazine on the passenger’s seat.

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“They are practically adults, but they don’t think like adults,” Carl Kalista, Rocklin resident.

The day before that, a 13-year-old boy stabbed a 14-year-old girl on a Stockton Elementary campus.

That student is now facing attempted murder charges.

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Police say while the gun wasn’t used, the crime of bringing a gun on campus is a felony offense.

“We do you take those incidents very seriously,” Jensen said.

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Parents say in this climate of mass shootings on school campuses, there’s a major cause for alarm.

“I just can’t believe somebody would do that especially now, knowing what could happen, everybody knows. It’s just so scary,” said Emily Mobley, a Rocklin parent with two students in the district.

And the reason may have seemed innocent, but was far from it.

“I think that he thought there was a level of humor and bringing a firearm to school,” Sgt. Jensen said.

Both police and parents warn this is no laughing matter.

“It’s not a joke, everybody knows it’s not a joke, not in this time,” Mobley said.

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Clark has been charged with a felony and was taken to jail. His bail has been set at $25,000.