Ahmed, who was discovered by police officers, died at the scene despite resuscitation attempts. A post mortem was carried out on Saturday but the cause of death has not been released.
Police, who have arrested an 18-year-old man and a 15-year-old boy, said on Sunday they were treating it as a racist incident, the British Broadcasting Corporation reported.
"Language and comments that were overheard by witnesses at and immediately after the incident led them to believe this was a racist incident," said Superintendent Andy Durkin of Greater Manchester Police.
"I would like to stress that the motive for the attack remains unknown at this stage and is a significant line of inquiry. The cause of death has not been conclusively established and further tests are being carried out.
A mosque was firebombed in Bolton in the days following the Sep 11, 2001 terror strikes in the United States.