The hero of the 2011 summer riots, Tariq Jahan, tells Channel 4 News he has lost faith in the justice system, after an IPCC report into the police investigation into his son's death.

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Tariq Jahan was widely praised for the way in which he helped prevent a race riot in Brimingham, just hours after his son was killed in the disorder. He was courted by the press, politicians and the public. He met the prime minister and even Prince William and Kate.

But nearly three years on, he told me he feels betrayed, with little prospect of ever seeing justice for his son's death. "I had just lost my son. The police were using me to quell the riots, they put me up on a platform and used me to promote non-violence. My mistake was I had faith in the justice system. I expected to get justice, all I got was a slap in the face."

His 20-year-old son Haroon was killed along with two brothers, Shazad Ali, 30, and Abdul Musavir, 31. They had been out in the early hours of the morning helping to protect local businesses from looters, during the height of the riots.

Run over

The three men were run over by a car travelling at speed. The atmosphere on the streets of Birmingham was extremely tense, with some groups calling for revenge. Mr Jahan was credited with restoring calm, urging local youths to put their faith in the justice system.

Eight men were charged and a trial began in 2012 at Birmingham crown court. But after two months of evidence, it was dramatically halted, when it emerged that West Midlands police had failed to disclose that key witnesses had been offered immunity from prosecution.

There are strict rules surrounding immunity arrangements, which must have the authorisation of the CPS and have to be made available to the defence in a criminal trial.

As he tried to explore the facts of the non-disclosure, the trial judge, Mr Justice Flaux, accused the senior investigating officer, DCI Anthony Tagg, of lying under oath, saying he had invented an account about the matter. It was hugely controversial and there were calls for the chief constable to resign.

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Three men were killed in Birmingham during the riots. Shazad Ali was newly wed - his wife Khansa was four months pregnant when he died and she is now bringing up their son Abdul alone. I spoke to Khansa and to Shazad's sister, Sumera (see interview above). She told me she is now calling on West Midlands police to reopen their investigation.

The judge had to direct the jury to disregard much of the evidence and the eight men were cleared. The IPCC launched an investigation and Channel 4 News has seen a copy of its findings, which are expected to be published on Wednesday.

The watchdog has cleared DCI Tagg of any wrongdoing, concluding that he had no knowledge of the immunity deals at the time they were offered.

Immunity deals

It finds that another officer, Khalid Kiyani, offered the deals in the immediate aftermath of the deaths without following proper procedure and without the knowledge of his superior officers.

The report concludes that Mr Kiyani has a case to answer for gross misconduct. However, he has since retired and so will face no further action. Questions are now being asked about why only one officer, a man with 30 years' experience, is being blamed.

Mr Jahan said: "Maybe Khalid Kiyani is a scapegoat being used because he's now retired. And no-one else is being blamed for the incompetence of the police force. Where were all the senior officers, why were there no notes made, why are bits and pieces of information missing?"

The watchdog states that in the immediate aftermath of the high-profile murders, West Midlands police were under huge pressure for results. But some of the eyewitnesses were themselves under investigation because they'd been guarding the local businesses with weapons.

Mosque meeeting

As Mr Jahan tried to calm the crowds, away from the cameras, a tense community meeting was held at a local mosque. We have spoken to a number of people who were there, who say Mr Kiyani was not the only police officer at that meeting.

Abu Sufyan, a youth worker who attended, told me: "The police had initiated this meeting in the mosque, where the subject was to offer immunity to all pepple who were at the scene as witnesses.

"There were about 10 officers there, they steered the meeting and mentioned that they would offer immunity. All they wanted was a witness statement about what people saw happened with these cars."

I asked him if all of the other officers were there when the immunity deal was offered, and he said they were.

"Yes. All the officers were there when they said that, nobody objected, nobody spoke out against it, nobody offered anything different, nobody said anything different, so it was almost an endorsed action."

Acted alone

Despite the testimony of those who were there, the IPCC has concluded that one officer, Khalid Kiyani, acted alone - an officer who has now retired and therefore cannot face disciplinary procedures.

Tariq Jahan has been left to face the prospect that he may never see justice for his son or the other two young men who were killed.

"We all lose loved ones, I accept that. What you don't expect is the injustices of this world. I had everyone standing with me because of what I said - councillors, MPs, people from government, everyone praised me. And now, nothing. You try and talk to these same people, they don't have time, they don't want to know, they don't care."

The report will be published on Wednesday and Mr Jahan and the family of Shazad Ali and Abudul Musavir will hold a news conference to respond at 12.30 in Birmingham. West Midlands police said they would not comment until the publication of the report.