Norwich ― Norwich Technical High School was placed in a lockdown Wednesday afternoon after three .22-caliber bullets were found in a school hallway, school officials and state police said.

The report came in at 12:51 p.m., when the school was placed in what state police termed a “soft lockdown” while a state police K9 unit that can detect firearms was brought in to search the school.

State police responded to the school and are working with school resource officers to investigate the incident, a letter sent to parents by school officials said.

“Our investigation has revealed that there was no intent for harm, and we are confident that there is no imminent threat to the safety of our students and staff,” the letter said. “We understand that this situation has caused concern throughout the school community, but we want to assure you that all necessary safety protocols were followed during the investigation.”

State police declined to release further information. An official at the school referred media calls to the state technical high school system central office. Phone messages left at the superintendent’s office and the executive director’s office were not immediately returned.