A gang of nine teenagers attacked a woman in her fifties in Brighton and left her with a broken arm.
They pushed her to the floor and one of them indecently exposed himself before stamping on her arm, breaking it.
The attack happened behind Aldi in St Peter’s Street, off Providence Place, Brighton, between 9.30pm and 10.30pm last Thursday (2 December).
Detective Constable Chris Bishop said: “The unprovoked assault has left the woman shaken and with a serious injury.
“There were many people around at the time including the group of around nine men in their late teens.
“I am appealing to anyone who witnessed the assault to come forward to assist us in this investigation.”
The suspect is described as being in his late teens to early 20s with dark skin.
Anyone with information is asked to contact Sussex Police on 0845 6070999 or to call the independent charity Crimestoppers anonymously on 0800 555111.