The San Bernardino County Sheriff's Department foiled a mass shooting plot at a local high school after a concerned citizen informed them of the student's sinister plans.
The unidentified teenager had a hit list with 33 names—students and teachers at Encore High School for the Arts in Hesperia—as potential targets who "could have been shot at the school," reported the Los Angeles Times.
"This threat all surrounded a shooting at the school that this student was going to be involved in," said Sheriff John McMahon.
Detectives also received a report of possible explosives on the school's 16955 Lemon St. campus, prompting a search by the sheriff's bomb squad and police dogs that turned up nothing.
Police became privy to the plot on Sept. 17 after receiving a report from a parent regarding the threat. Further investigation revealed threats on social media. The following day, in conjunction with school officials, police identified the student but there wasn't probable cause to make an arrest.
Detectives continued to interview students and teachers, and on Sept. 20, they obtained a search warrant for the student's parents' homes, where they found legally registered firearms.
"Our deputies discovered information that supported those threats," McMahon said."The information we have at this point is he was the lone suspect in this plot."
The teenager was arrested on Tuesday evening and is being held at High Desert Juvenile Detention Center. His parents are cooperating with the investigation.
McMahon declined to reveal the motives for the attack to not hinder the prosecution of the teenager.
In a letter to parents on Wednesday, the school stated that the student was no longer permitted on campus.
"One of the things that everyone should take from this investigation is that it is important for students, parents and staff to always remember that if you hear something, you should say something," read the letter. "We want to make sure that all of our people know that we take these reports seriously and that we will act on these reports to make sure that our family is safe."