During a special session, the Rochester School Board last week expelled two students accused of phoning in bomb threats that disrupted four Rochester schools.

The students, who earlier had been suspended, made the threats in mid-December, forcing the schools to evacuate the buildings and requiring authorities to enforce increased security measures. Four bomb threats were called in to three middle schools and a fifth was made to an elementary school.

It's unclear if either of the two students will face criminal charges. The special session was called because state law requires a maximum period of 10 school days between a student's suspension and an expulsion.

"The safety of our students and our staff is a top priority," Superintendent Michael Munoz said in a statement. "We work hard to keep our schools safe and encourage parents to speak to their kids about the negative impacts of bomb threats so that together, as educators and parents, we are protecting our kids."