DANVERS (CBS) – St. John’s Prep in Danvers is increasing security after threats were discovered in a bathroom.

The high school sent out a letter to parents and students after a threatening message was found for the second time. No students were mentioned in the threat, but the writings mentioned Friday morning specifically.

READ MORE: Westford Academy To Change 'Grey Ghost' Mascot After Complaints

Danvers Police officers will now have a presence on campus and backpacks are banned. Students may only carry clear, plastic bags on campus.

Other precautionary measures include “limited and monitored access to bathroom facilities” and restricted access to the school after classes have ended.

READ MORE: More Than 1,200 Mass. Kids Test Positive For COVID-19 This Week

“It is the unsettling reality of our times that we find ourselves faced with this situation at St. John’s,” Headmaster Edward Hardiman said in the letter to parents. “We believe, however, that these measures, while they may seem inconvenient, will help ensure the safest possible environment for our students, faculty and staff.”

The increased security begins Tuesday.

MORE NEWS: 7-Year-Old Girl Grazed By Bullet On Talbot Ave. In Dorchester

St. John’s Prep is a Catholic secondary school in Danvers with more than 1,100 students from approximately 80 different communities.