Officers were called to Admiral Casino in Nottingham’s Clumber Street after a member of staff was punched after asking a customer to leave because he was shaking a slot machine.
In the incident on December 9, 2022, the victim suffered a fractured eye socket.
Police have now released an image of a man they want to find and are asking the public for help in identifying him.
PC “This was an appalling assault,” Matthew West of Nottinghamshire Police said.
“We believe the man in the image will be able to help us with our inquiries. If you are the man in this image or know who he is, please call 101 and quote crime number 23*722794.