LIVERMORE (CBS SF) — Security was heightened Thursday at Livermore High School after a student was arrested for allegedly issuing threats to harm classmates, district officials said.

In a message to parents, Livermore Valley Joint Unified School District Superintendent Dr. Kelly Bowers said: “Last evening, we received word that one of our Livermore High School students made an alarming statement to other students, threatening to cause harm on our LHS campus today.”

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Investigators took the student into custody on Wednesday night.

“The individual who made the remarks remains in custody and we are confident that any possible threat has been neutralized,” Bowers wrote “School and activities will proceed as usual without interruption.”

But as a precaution, there was a heightened presence of Livermore police officers and district officials at the school.

Police said a student spoke up and reported the threat.

“Yeah it’s kind of scary you could think that something could happen.,” said one Livermore High School parent.

“I heard people talking about it that there was police on campus and that made me feel safer,” said a Livermore High School student.

“I heard he had a list of names he was going to try to kill,” said another student.

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“What’s going through my mind is my grandson was saying, ‘Are you sure you want me to go to school, grandma, until we see what’s going on?’ and I told him, ‘Well, you’re going to have to go to school no matter what.’”

On Thursday, Bowers brought her dog Boomer onto campus to help comfort students. She says the school district and police department took immediate action when the threat was first reported.

The superintendent said the arrest was a case of “see something, say something.”

“It was pretty amazing, we had students who reported the concern, they told their trusted adults, the trusted adult told the administration, we contacted police, and our student resources officer and everybody mobilized to get to the root of the concern,” said Bowers.

“When somebody sees something they should no matter what,” said a parent.

The threats come at a time when students at school were still dealing with the lingering emotions from a tragic car crash that claimed the life of a classmate and left five others with serious injuries.

On Aug. 28, the teen was in a pickup truck when it crashed, rolled over and plunged 200 feet down an embankment on Del Valle Rd. near Mines Rd. in unincorporated Livermore.

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He was identified as Hunter Diemert, a junior at the high school, who was a fixture on the school’s wrestling team.