A 17-year-old boy from London received various injuries to his body after being assaulted in Eastbourne on Friday night (September 12).
He received minor injuries to his arms and legs and a more serious one to his face while at a property in Firle Road around 10.43pm.
Police believe he then left the property and walked along Seaside where door staff at Buskers Bar called emergency services and he was taken to Royal Sussex County Hospital to be treated.
Detectives say he is not co-operating with police in their inquiries.
Anyone with any information or saw what happened is asked to contact police on 101@sussex/pnn.police.uk or call 101 quoting serial 1730 of 12/9.