FULLERTON, Calif. (AP) — Two Orange County teenagers have been arrested after they were overheard discussing a school shooting that would be “bigger than Columbine.”

Fullerton police said in a statement that a fellow student overheard the comments from the two 16-year-olds at an athletic event Wednesday at Troy High School and reported it to an officer assigned to the school.

The two talked about plans to “shoot up” the school and discussed different types of guns and their effectiveness. The student witness took a photo of the two to share with the officer.

Police also found that the suspects had done internet research on prior school shootings and weapons.

The two teens were arrested on suspicion of making criminal threats and conspiracy to commit a felony. They are being held at juvenile hall. Their names have not been released because they are minors.