A teenage girl temporarily lost her hearing after being assaulted by a woman in a town centre in Northamptonshire.
The woman was verbally abusive towards the victim before hitting her on the side of the head in the middle of Daventry between 1.10pm and 1.20pm on July 30.
A female member of the public intervened and prevented the girl from being further assaulted in Bowen Square.
The offender is described as a short, white woman, aged 40-50 and wearing a white cardigan, blue trousers and a crocheted hat.
Witnesses or anyone with information, particularly the woman who intervened, are asked to call Northamptonshire Police on 101.
Alternatively, call Crimestoppers anonymously on 0800 555111.