The public response to an appeal over an attack which left a rugby league supporter critically ill has been "disappointing", police said.
Halifax fan David Singer, 32, suffered serious head injuries when he was set upon outside Halliwell Jones Stadium, Warrington, on 26 September.
Police believe an appeal broadcast at the Super League Grand Final on Sunday reached about one million people.
Cheshire Police said they had received only a small number of responses.
Mr Singer had been in Warrington to watch his town's team play Featherstone Rovers in the Championship Grand Final.
Inquiries have suggested that the attackers were wearing Featherstone colours, and targeting Halifax fans as they moved back to their transport in the car park.
Officers believe there may be other Halifax supporters who were subjected to abuse or violence before Mr Singer was attacked.
The force broadcast its appeal on the screens at Old Trafford on Sunday, and it was also relayed on Sky Sports.
Det Insp Stephen Jones, leading the inquiry said, "When you consider over a million people would have heard or seen the police appeal, the small number of calls we received is disappointing.
"I know that the assault on David was witnessed by both Featherstone and Halifax supporters.
"I also believe that other Halifax supporters were verbally abused and had aggression directed towards them as they left the stadium - perhaps by those responsible for assaulting David Singer.
"The fans hold the answer to who attacked David, and I would urge anyone with any information to come forward and make contact with police."
Despite the relatively low number of calls, police said the information had been useful to the investigation.
Detectives were following up new lines of inquiry on Monday.
Mr Singer has been critically ill in a coma since the attack.