Officers rushed to the Portsmouth Public Library after an employee called 911 to report other kids had assaulted a 12-year-old at the facility.
They said the boy was safe in their meeting room and that the library had security footage of the assault.
An officer took the boy home and took information for a report.
Then, police headed to the home of one of the suspects and took him into custody. The juvenile was processed at the police station but eventually released into the care of his father.