Norwich — Officers and K-9 units from several police departments arrived at Kelly Middle School on Thursday morning for an unannounced narcotics sweep of hallways and common areas while students and teachers were kept in their classrooms during first period.

The search, with eight K-9s and officers from Norwich, Plainfield, Colchester, Stonington and Waterford police, took 30 minutes. Each team of two dogs and handlers was accompanied by two Norwich school administrators.

“Nothing was found,” Norwich Superintendent Abby Dolliver said later. “It was a good exercise, a good training program.”

Dolliver said students and teachers were not involved in the search and were not informed ahead of time. Teachers were told only to hold students “in place” while the search was conducted.

Dolliver sent school messenger voicemails to parents after the search was completed. Separate messages were sent to other Norwich school administrators, to the Board of Education and to Kelly teachers and staff not involved in the search.

Dolliver said the search was routine and not in response to any suspected drug problems at the school. A similar search was held last school year.

“We don’t have a problem,” Dolliver said, “but we wanted to be proactive.”

Kelly houses 687 students in the seventh and eighth grades this year. The school will convert to a sixth-through-eighth-grade middle school next school year with a science, technology and arts magnet theme.

c.bessette@theday.com