Three students from two San Bernardino County high schools were arrested this week for allegedly making two unrelated threats against peers on social media that authorities determined were credible.
In separate cases, detectives with the San Bernardino County Sheriff's Department investigated rumors of a potential campus shooting at Los Osos High School in Rancho Cucamonga and at Alta Loma High School.
At Los Osos High, campus police and Sheriff's Department investigators interviewed 27 students and two faculty members about rumors of a possible shooting, which led to some dead ends, authorities said.
"All students interviewed continued to point their fingers at each other, stating they heard it from the other one," the Sheriff's Department said in a statement.
But the questioning eventually narrowed the investigation down to one boy and one girl, both 14. When a sheriff's deputy looked through the male student's phone with his consent, text messages that spread the threat rumors were found, officials said.
The female student was called in from home and also questioned. Both students were ultimately arrested Monday on suspicion of conspiracy to commit murder. Their identities have not been released because of their ages.
While investigators on Monday were dealing with the Los Osos High School threats, officials say 18-year-old Alta Loma High School student Andrew Riccardi had posted a threat on Twitter about shooting up his school.
The post stated, "Well mom said I had to go to school better pop the trunk first," along with a picture of what appeared to be a real gun, officials said. Authorities saw the post and arrested Riccardi at school in front of his classmates.
Riccardi said the gun was a replica but the school principal "felt it was a credible threat and feared for the other students' safety," the department said in a statement.
Riccardi's parents were told what happened and agreed to let authorities search their home. Deputies found Riccardi's father had guns but noted they were locked in a safe that requires fingerprint ID to open – making them inaccessible to the teen.
But detectives also found weapons in Riccardi's room, officials said. He was arrested on suspicion of possessing a weapon at school, possessing nunchucks and having two large fixed-blade knives in his car on campus.
The students are just the latest among several to be confronted by law enforcement in recent months for making allegedly threatening posts on social media.
On Monday, the Los Angeles County Sheriff's Department said it had detained a person for making threats on Instagram against a fellow middle school student in San Dimas.
Two weeks ago, two South Pasadena High School students were sentenced to probation for making criminal threats in what police initially said was a potential "massacre" plot.