A man was left unconscious and with broken bones after a group reportedly attacked him and his friend.
They were walking along Clinton Street, going towards Lower Parliament Street, in Nottingham city centre when they were approached by a group.
It is alleged that a member of the group punched the man, causing him to lose consciousness and leaving him with a broken jaw.
Other members of the group are then reported to have turned on his friend, kicking him and punching him several times and leaving him with minor injuries.
Officers investigating the incident, which happened at around 3am on Saturday 25 September 2021, have now released images of five people they would like to speak to, and who they believe might have information that could help with their enquiries.
Detective Constable Raj Johal, from Nottinghamshire Police, said: “The potential consequences of such actions can be devastating. One punch can cause a huge amount of damage and as such these reported actions are being taken extremely seriously.
“The victim and his friend are thankfully recovering but we understand the impact such an incident can have and continue to offer support.
“Officers are working hard to understand the circumstances around the incident, and are really keen to talk to the people pictured. We believe they could help us with our enquiries and investigation into the incident.
“We would urge anyone who recognises the people in the image, witnessed the incident or has any information to call 101, quoting incident 142 of 25 September 2021.”