Police want to speak to anyone who filmed a fight involving two 19-year-old girls in Liberation Square at the weekend.
They were having an argument between 2:05 and 2:10 on Sunday morning when one of the girls, wearing a blue denim jacket over a green crop top, attacked the other.
It caused injuries to the girl's hands, arms and head - but she didn't go to hospital.
Officers think several people recorded the attack and want anyone with footage to come forward.
Anyone else who may have seen this or who has any information is asked to contact police on 612612 or the independent charity Crimestoppers anonymously on 0800 555 111 or via their Anonymous Online Form at Crimestoppers-uk.org.