A 16-year-old boy was arrested last week after police received a tip that he was recruiting fellow students in a plot to carry out a mass high school shooting in Berkeley, California. 

The Berkeley Police Department said in a statement the tip came on May 21 and there was an alleged plan in the works to target Berkeley High School via a shooting and potentially with a bomb.

That prompted police to obtain a search warrant for the teen’s home and authorities acted swiftly, as parts of explosives and assault rifles were found in the boy’s home. Several knives and electronic weapon devices were also discovered on the scene. 

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The teen, who is unnamed because he’s a juvenile, turned himself in Monday and was assessed by a mental health response team upon his arrest on suspicion of possessing destructive materials and threatening to commit a crime that could cause bodily harm.

Berkeley Unified School District Superintendent Brent Stephens thanked those who came forward in a letter to the school community. 

“Speaking up in this instance allowed for the police to intervene in advance of any harm occurring,” Stephens wrote.

The teen’s arrest comes a week after a grade school shooting in Uvalde, Texas that saw 19 children killed by a teen gunman. And less than three weeks ago, 10 people were killed in a racially motivated shooting at a Buffalo, New York supermarket.

It also comes a little over a month since California Berkley’s campus was temporarily shut down from a “credible campus-wide threat.”