Four teenage boys have been arrested for plotting a mass shooting at their Northern California high school. The boys reportedly had a list of potential targets, which included both staff and fellow students.

The boys all attended Summerville High School in Tuolumne County, and their plot was uncovered on Wednesday when a group of fellow students overheard three of the boys discussing the plot while on campus. School staff was notified and the boys were removed from campus and searched for weapons. No weapons were found on them, and a subsequent search by the Tuolumne County Sheriff's Department uncovered no weapons at their homes either, reports the Union Democrat. The investigation revealed there was a fourth accomplice in the plot, and all four boys were arrested on Friday.

At a press conference on Saturday afternoon, Sheriff James Mele said their plans had a specific list of individuals to target and was set for a specific school event. Mele would not say which specific event was targeted, fearing a potential copycat shooting, and said the parents of the targeted individuals would be contacted after the investigation was complete. While the boys did not have any weapons in their possession, Mele said the boys were "pretty dog-gone close," according to The Modesto Bee, and reportedly had plans on how to obtain them. The boys confessed to investigators that they had been planning the attack.

"At this time I want to reassure the community that there is no further threat to the students or staff," said Mele.

Mele said he had "no idea" what the motive was when asked, and added, "I do know the discussion needs be: How do we stop this violence? Because it's not just gun violence. This is an issue of violence on our campuses."

The sheriff also commended the students who reported the boys, saying, "Their willingness to get involved prevented what well could have been another needless tragedy."

All four boys have been charged with conspiracy to commit an assault with deadly weapons and transferred to a juvenile detention facility in another county, since Tuolumne County has no such facility.