Police arrested a 13-year-old Wednesday accused of posting threats against Hamden High School and Hamden Middle School.
The threats were posted on Instagram Tuesday, police said.
The teen is a student at the middle school, according to police.
He is charged with first-degree threatening and second-degree breach of peace and is scheduled to appear at New Haven Superior Court for Juvenile Matters on December 20.
Hamden High School was closed Friday, Monday, and Tuesday after threats received last week. Students at the high school returned to class Wednesday, waiting in long lines to get into the building after school officials decided to use metal-detecting wands to screen everyone coming into the school.
Hamden is one of several communities that has dealt with a string of school threats in recent days.