Officials say security measures were stepped up out of an abundance of caution. (Dover Bay Secondary School)

For the third day in a row, security guards will continue to patrol three Vancouver Island schools and the school district office because of concerns over a disgruntled employee.

CBC News has learned a Nanaimo teacher who pleaded guilty this week to uttering threats has been suspended from teaching in the district since last September.

Nanaimo, B.C.

RCMP in Nanaimo confirm it's the same employee who prompted the added security at Dover Bay High School, Nanaimo Secondary School and Celaire Elementary School.

RCMP Const. Gary O'Brien confirms the employee is Francies Willem Van Der Voort Maarschalk.

"That individual was charged with several criminal offenses involving threats,” O’Brien said.

“As a result of that, we've increased security around several buildings where this person has had contact in the past."

The school board says the decision on whether to continue with the added security will be made on a day to day basis.

With files from the CBC's Lisa Cordasco