Detectives are hunting the victim of a reported assault in Canterbury who left the scene before officers arrived.
The assault took place in the High Street at just after 11.20pm on Saturday September 10.
Officers were alerted by CCTV operators and a man was arrested on suspicion of affray at 11.35pm.
Sgt Paul Barrell said: “This appeared to be an unprovoked assault on a man who made no attempts to fight back.
“A member of the public intervened and the offender made off in one direction and the victim left in the opposite direction before police arrived.
“We urge him to come forward so we can ensure his welfare needs are being met. We would also appeal for the member of the public who bravely stepped in to intervene to contact us as they could have important information that could help with our investigation.”
If you can help please contact Kent Police on 01843 222289 or Kent Crimestoppers anonymously on 0800 555111 quoting reference ZY/32128/16.