A cryptic bomb threat at King’s Fork Middle School, the fifth to hit Suffolk’s public schools recently, sparked a Code Yellow Wednesday.

The message written on a stall in a boys’ bathroom — “Bomb Threat 2:12 5.3.1” — was reported during the morning, Principal Jennifer K. Presson wrote in a letter to parents.

Police and fire investigators reported to the school to assist in the investigation, and bomb squad dogs were brought in as an additional measure, according to Presson.

“During the building check our faculty, staff, and students followed Code Yellow procedures in which instruction continued but no movement was allowed in the hallways,” Presson wrote.

“We resumed our regular schedule without a loss to instructional time.”

Previous bomb threats on bathroom walls were discovered at King’s Fork High School on April 24, King’s Fork Middle School on April 26, and Lakeland High School on April 22 and 23, while threats on social media of a “shoot out” and explosion at King’s Fork High School were reported to administrators on April 25.

Those threats also sparked Code Yellows, along with random metal detector checks, extra city and fire officers at campuses, and high rates of student absenteeism.

Presson, stating that student safety “continues to be a top priority,” urged parents to “discuss the seriousness of the situation” with their children.

“It is important for students to understand that the culprit, once identified, will face criminal charges,” she wrote.

She urged anyone with information to contact the school or Suffolk Police Department.