Special video report: The streets that divide Sheffield’s gangs

Rashid Chaiboub said he had lost faith in the system after South Yorkshire Police emerged largely unscathed from an independent investigation into its contact with his son Tarek, 17.

Tarek, who had acquaintances in Sheffield’s rival “postcode gangs” S3 and S4, was shot dead outside a barber’s shop in the Burngreave area of the city on July 11, 2008.

Five days before the killing, Tarek he been stabbed seven times in an ambush outside his family home.

Mr Chaiboub complained that police had not properly investigated the first attack and only made serious inquiries after Tarek’s murder.

But the Independent Police Complaints Commission (IPCC) found that officers had worked “diligently on the case”, only to be hampered by Tarek’s refusal to help the inquiry.

The watchdog found that gang culture might have deterred him from naming his attackers.

Mr Chaiboub said: “We are very upset about this decision. If this is how the police do their job, then good luck to them and goodbye.

“I have been talking about this issue for a long time, and I have consulted my solicitor, but I have not got anywhere with my complaint. Nobody is listening to me.

“It seems that, all the time, it is decided that the police are doing the right thing – 100 per cent.

“If they do the right job, I am happy, but I do not think they did the right job for my son.”