COEUR d’ALENE — School board members in Coeur d’Alene voted last week to expel three students from the school district.

The expulsions come in the wake of threats of violence and offensive images that were posted earlier this month on social media and involved Lake City High School students.

The Coeur d’Alene Police Department, working with the school district, investigated the messages and identified the students who sent them.

“On Thursday and Friday, the Board of Trustees held three student disciplinary hearings. The board voted to expel three students. By law, individual student disciplinary matters are confidential,” said a statement released Monday by the school district. “The board’s decisions were made in the best interest of the health and safety of all students. Further, students need to know their conduct on social media can be grounds for suspension or expulsion.”

The series of threats, which began Oct. 6, led school officials to tighten security at the school. Lake City High students were not allowed to leave campus at lunchtime and cellphone use was restricted.

The first threatening social media post included a photo of a student with a weapon and a derogatory message about Lake City High School cheerleaders.

Another online threat targeted Lake City High School students and staff and was made in a group chat with about 250 users who appeared to be students.

The following day, a photo of a Lake City student holding a rifle with a caption referencing a “threat list,” was posted on social media. The student who posted that message was arrested and is facing four misdemeanor counts of using the telephone to terrify, threaten or harass, in addition to the school district’s disciplinary action.

The other students were identified in the course of the investigation.

The students’ names have not been released, because they are juveniles.

Expelled juveniles fall under the purview of Idaho’s Juvenile Corrections Act. Idaho law requires school districts that expel students who would be considered truant to notify the local district court when such a student is expelled.