Six youths have been released on bail while police investigate a "happy slapping" attack that turned into a brawl.
A gang of eight teenagers were involved in an attack on salesman Curtis Mulcare in Imperial Arcade, Brighton.
Mr Mulcare, 31, fought back against the teenagers and knocked one of them unconscious. Another suffered a head wound in the fracas on Monday.
Both injured youths were taken to the Royal Sussex County Hospital for treatment and were later released. Neither had sustained serious injuries.
A group of six 16 and 17-year-olds from Brighton were arrested on suspicion of affray and questioned, before being released without charge.
Officers from Sussex Police were yesterday going through dozens of statements from witnesses to the incident and viewing CCTV recorded in the area to try to identify who was involved.
It is alleged one of the arrested youths was responsible for throwing a brick through the glass roof of Imperial Arcade, which caused it to be closed to the public.