Emergency services were called to Kingscote Way in Brighton at around 9.50pm on Monday (July 3) to a report of a man having been assaulted.
A local man was taken to hospital by the ambulance service for treatment.
An eyewitness reported the use of petrol in the attack.
Police a carried out an extensive search of the area, supported by the police helicopter.
An investigation is ongoing to establish the full facts of what happened and locate any suspects.