A glass bottle was reportedly thrown at a man's head, injuring him, at a pub in Doncaster.
The bottle is believed to have been lobbed during a disturbance at the Coach and Horses on Scot Lane in the town centre.
A 41-year-old main sustained a minor head injury in the incident, which happened on Saturday, September 9 at around 7.15pm.
Police, who issued a dispersal order that evening to prevent further violence, have now appealed for witnesses.
Chief Inspector Jayne Forrest said: "An investigation has now been launched and anyone who may have witnessed the incident, or has information that may be able to assist with our enquiries, is asked to please report it to us.
"In this instance the victim sustained minor injuries. However, it could have very easily been much worse. I would like to offer my reassurance that this type of behaviour is not tolerated and we will take action where necessary to keep members of our community safe.
"We work closely with all of our licensed premises across Doncaster and I would encourage anyone who witnessed the incident, or has information that may be able to assist us with our investigation, to please report it via 101 quoting incident number 846 of September 9. Anonymous information can also be given to Crimestoppers on 0800 555 111."