Police have been given an extension to question two teenagers arrested on Friday after an attack in Brighton.
A 36-year-old local man was assaulted in St James's Street between 23:30 BST on Thursday and 00:30 BST on Friday.
He is in a critical condition with head injuries at Hurstwood Park Neurological Centre, Haywards Heath.
The 18-year-old man and 17-year-old boy arrested on suspicion of causing grievous bodily harm can be held until 01:40 GMT on Monday, magistrates ruled.
A motorcycle helmet which police were looking for on Saturday has been found, a spokesman said.