A man sexually assaulted and groped 18-year-old woman in Northampton town centre in the early hours of Sunday (January, 29).
The woman was joined by the man as she left a pub in Abington Square and they walked together in the direction of Abington Street, between 4am and 4.40am.
Once they reached Abington Street the man grabbed hold of the victim and kissed her at which point she pushed him away.
He took hold of her again and grabbed her breast before she managed to push him away again and seek help.
The offender was mixed race and in his late teens, about 5ft 5ins and of slim build.
He had afro-style hair and wore a grey hooded top and black jeans.
Officers would like to speak to anyone who may have witnessed this incident or who may have any information regarding it.
Witnesses or anyone with information about this incident can contact police on 101 or Crimestoppers anonymously on 0800 111 555.