Sussex Police is seeking witnesses to an assault in Bond Street, Brighton.
The incident took place just after 5am on Friday , September 28.
Officers are particularly keen to hear from two passers-by who appear to have witnessed the assault – one was wearing a hi-vis jacket and a hard hat, and the other was a young man wearing a black and white puffa jacket or anorak.
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The victim, a 20-year-old local man, sustained serious facial injuries, police said.
A 21-year-old man from Brighton, arrested on suspicion of assault, has been released under investigation.
Anyone with any information is asked to report it online or call 101 quoting serial 163 of 28/09.