Lincolnshire Police are appealing for the victim of an assault on Lincoln High Street before Christmas to come forward.
A man was attacked between Clasketgate and Steep Hill at around 3am on December 22.
The victim is described as white, of medium build, with short dark hair.
He is aged between 25 and 30.
An 18-year-old man was arrested and released under investigation.
A police spokesperson said: “We are asking that the victim come forward and speak to officers to help with their enquiries.
“This attack had come a few minutes after an unrelated assault in the same area.
“If you are the person we wish to speak to, or have any information related to the enquiry, call 101 and quote incident 34 of December 22.”