Detectives investigating after trouble flared on Birmingham's Broad Street which left a man from Tipton injured have today released CCTV images of a number of men who could be involved.
Around 20 people were involved in the fracas just before 4am on Sunday 29 September which saw the man, aged 39, knocked unconscious and repeatedly stamped on as he lay on the floor.
The victim received hospital treatment for a gashed head.
Police officers were also pelted with bottles, stones and traffic cones.
Five men aged between 19 and 25 remain on police bail while detectives investigate what sparked the disorder and identify others who were involved.
Det Ch Insp Tom Chisholm, from force CID, said: "This was a serious disorder that involved large crowds of people who were in the Broad Street area around closing time. It took considerable effort to clear the street during which officers were subjected to verbal and physical abuse.
"We have trawled hours of CCTV to identify people that we think played a part in the violence. We are releasing these images and asking the public to help identify them.
"Police officers have been working hard with the businesses along Broad Street to reduce incidents of violence and thankfully disorders on this scale are rare. The vast majority of people who visit Broad Street, or the other city centre entertainment venues, are out simply to have a good night with friends."
Anyone who can identify the men in the images should contact police on 101 or Crimestoppers on 0800 555 111.