A father-of-four who was attacked by a teenage gang outside his Salford home has undergone a third operation to relieve pressure on his brain.
Mr Carroll had been working on his car outside his home
Phillip Carroll is critically ill after he was attacked by three teenagers who he confronted at his house in Lower Broughton, Greater Manchester.
Mr Carroll, 48, suffered serious head injuries after challenging the youths who threw a stone at his car on 13 May.
Police said the operation had been a success and his condition was "stable".
Mr Carroll and his brother, John, were working on his Range Rover when the attack happened on Friday night at Grecian Street North in Lower Broughton.
He has previously undergone two operations at Hope Hospital in Salford.
Mr Carroll has undergone two operations since the attack
His wife, Jean, 44, and four children were at his bedside on Thursday.
Greater Manchester Police said they believed people may not be coming forward with information because they are scared of retribution.
On Thursday a police spokesman said they were "pursuing a number of lines of inquiry."
"However, we are continuing to appeal for further information that may help trace the people responsible for this attack."
Officers are also trying to trace a teenage girl who rang an ambulance to help Mr Carroll.
She was described as about 14 or 15 years old and was wearing white trousers.
One of the offenders was described as white, about 6ft tall, and was aged 15 to 17 years old. He was wearing a dark-coloured baseball cap and a black long-sleeved, waist-length waterproof coat.
The second was also white, about 5ft 10in tall, of medium build and aged about 17. He was wearing a similar waterproof jacket to the first boy and dark blue denim jeans.
Officers also want to speak to a white girl, aged about 15 or 16, with shoulder-length dark hair.
She was wearing a very short dark brown crocodile-print skirt with dark brown round spots on it. She had a dark-coloured suede effect fitted jacket on and dark brown low heeled sandals.