A teenager lashed out at Daventry Library say police, kicking a sign and then pushing a member of staff.
The incident happened at around 11am on December 1 – Northamptonshire Police released the details on December 22.
It is alleged the teenager became disruptive in the library. He was asked to leave the premises at which point he kicked an advertising board before pushing the staff member.
The offender was white, aged between 17 and 20 and had short dark hair. He wore a dark coloured coat and grey tracksuit bottoms, black trainers and was riding a bike.
Officers would like to speak to anyone who may have witnessed this incident or who may recognise the description of the offender.
Witnesses or anyone with information can contact police on 101 or Crimestoppers anonymously on 0800 555 111.