A man had to be taken to hospital after being punched in a bar at the Xscape entertainment complex.
The 30-year-old from Castleford was attacked in the Winterseam Bar at the Glass Houghton venue at around 12.10am on Sunday, September 20.
He was approached by a man while stood at the bar who then punched him in the head causing him to fall to the floor.
He was taken to hospital where he is being treated for a serious but not life threatening head injury.
Det Con Laura Wheatley, of Wakefield CID, said: “This incident occurred between the entrance and dance floor at which time it was really busy with customers and would have been witnessed by a number of people.
“Anyone who saw what happened or has information is asked to contact Wakefield CID on 101 referencing Crime number 13150380026.
“Information can also be given anonymously to the independent Crimestoppers charity on 0800 555 111.”
A 27-year-old man from Pontefract, who was arrested on suspicion of assault, has been bailed pending further enquiries.