A 14-year old boy is recovering after being assaulted on his way home from school in Bakewell back in June.
The boy was walking along Butts Road in the town at around 4.30pm when he was approached by three other boys.
A man and his young son then walked past and the three boys are believed to have sniggered.
The man then shouted at the group, causing the three boys to run off, before he grabbed the 14-year old boy and pushed him into a wall.
Police are now describing the man who they want to talk to as being in his early 40s with black, greying hair and facial hair.
Officers investigating the incident are appealing for anyone who may have witnessed what happen or knows anything about it to contact PC Linda Hancock on 101, quoting reference number 16000174055.