Richard Mannington Bowes, 68, is currently in a coma after he tried to stamp out the fire which thugs started in a supermarket bin in Ealing, West London.
He remains in a critical condition in hospital today after suffering serious head injuries on Monday night on Monday evening.
Speaking from the scene of the attack, Detective Chief Inspector John McFarlane said he has been unable to contact the victim's family and appealed to the assailant to turn himself in.
The victim, whose identity was established only when locals recognised his description and officers used his keys to enter his house, remains critical on a life support machine.
Mr McFarlane said the investigation could turn into a murder inquiry.
The detective described the scenes surrounding the attack. He said a handful of officers, not wearing protective gear, arrived at 10.45pm to reports of looting at the Arcadia shopping centre.
The half dozen officers were massively outnumbered by scores of thugs and called for back-up as they were showered with missiles, including bottles. Read More