At 3.32am on Saturday November 24 police were contacted by the ambulance service who had been called to an injured man outside Bijou nightclub, in Chapel Lane.
James Ethrington, 24, of Bingley was taken to hospital with head injuries and was kept in hospital but has now died.
Four men aged 31, 30, 28 and 23 were arrested in connection with the incident. The 31 year old and 30 year old were released under investigation and the 23 year old bailed. The 28 year old was released without charge.
Det Chief Insp Ian Scott said: "I would appeal to anyone with information about the incident and who hasn’t yet come forward to do so. We are particularly keen to speak to anyone who took footage on their mobile phones to come forward.”
Anyone with information is asked to call police on 101 quoting crime reference number 13170551254 or call the independent charity Crimestoppers anonymously on 0800 555 111.