Police believe a man responsible for three attacks in Blackpool may be from Barnsley.
A CCTV image has been released showing a man detectives want to speak to over violence.
The incidents happened on Saturday, August 17, which left a 26-year-old man with a fractured skull, split lip and a bleed on the brain - and two other people with possible broken noses.
Police are urging members of the public to help.
Det Con Alan Quanbrough, of Lancashire Police, said: “These were nasty and unprovoked assaults and we need help to find the man responsible and bring him to justice.
“It is possible that the person responsible is from the Barnsley area.
“We have a really clear CCTV image of a man we are keen to speak to in connection with these assaults.
“I am more than certain someone will recognise him.”
n Anyone with information should call police on 101 or Crimestoppers on 0800 555111.