Police arrested a juvenile in connection with graffiti threats made at a Honolulu middle school Friday, a Honolulu Police spokeswoman said in an email today.

The juvenile, whose age and sex were not released, was arrested for first-degree terroristic threatening this afternoon, police said.

The case will be referred to Family Court.

Police did not identify the school, but students were locked in their classrooms for about an hour Friday morning at five schools in the Ewa-Kapolei area. The schools were Campbell High School, Ilima Intermediate and Kaimiloa, Pohakea and Ewa Beach elementary schools.

The students were kept in their classrooms from 10:15 to 11:35 a.m., just before lunch, the Department of Education reported.

Several students posted photos to social media accounts of a threat apparently written on a wall, dated March 4, that included a crude drawing of a gun firing at stick figures. The graffiti message alluded to a “m9 beretta” and warned to “Watch out, 11:05 a.m.”

The Department of Education also increased security personnel and police at Castle High School in Kaneohe and nearby areas Friday morning after school officials were made aware of a reported threat Thursday.