Police are looking for the person who recently broke two large windows at the Portland Public Library on Congress Street. The incident occurred shortly before 11 p.m. on Aug. 12, during an altercation in front of the building, said Sarah Campbell, the library’s executive director. Two 4-foot-by-8-foot tempered glass windows were struck during the incident, cracking the glass and causing $2,900 worth of damage, said police Lt.