The incident happened at about 12.20pm on October 14 in the underpass at the bottom of Comberton Hill.
Police are asking members of the community to help identify the girl pictured who may be able to help with inquiries.
She is described as white, around 20-years-old, slim build with dark hair in a ponytail and was wearing pink jogging bottoms with a jacket.
PC Angeline Stanley from West Mercia Police said: “We are appealing for witnesses that were in the area that may have seen the incident take place that could help with our enquiries.
"We are also appealing for anyone who thinks they may recognise the girl in the CCTV image as we believe she may have information that could help with our investigation.”
If you have any information, call West Mercia Police on 101, quoting incident 22/96817/19.
Alternatively, information can be given to the independent charity Crimestoppers on 0800 555 111 or via their website.