Sam Hallam has spent six years in jail for a murder he swears he did not commit. Now, he has received the news he thought would never come - that the case is to be reopened

Sam Hallam

When Sam Hallam was a teenager he was tried and convicted of a murder he says he did not commit.

Now, five years later, he is still a prisoner – number MW5897 – but from his cell in HMP Bullingdon in Oxfordshire, the 23-year-old is still pleading innocence.

Now it seems the authorities are listening. The Independent has learnt that Mr Hallam's case is to be re-investigated by a new police force, raising hopes that his conviction could eventually be quashed.

The revelation comes more than a year after this newspaper revealed that his case was being examined by the Criminal Cases Review Commission (CCRC), after a campaign group unearthed new evidence suggesting Mr Hallam's innocence. Now the CCRC has ordered Thames Valley Police to re-investigate a case originally handled by Scotland Yard.

It is a move which carries some significance. Since 1997, when the CCRC was formed, the organisation has completed 12,224 case reviews but only 44 have warranted a new police investigation. Of those, 26 were subsequently referred to the Court of Appeal, and 19 of those ended with convictions being quashed. If the new investigation concludes that Mr Hallam's conviction is unsafe it will be referred to the Court of Appeal, which will either order that Mr Hallam be retried, or simply acquit him.

Last night Sam's mother Wendy Cohen said: "We never allow ourselves to get too excited, but we are treating this as good news. We have got to be hopeful as it is another step towards our ultimate goal of having Sam home again."

Mr Hallam was convicted in 2005, at the age of 18, for the murder of Essayas Kassahun, an Ethiopian chef. Mr Kassahun, 22, was murdered on 11 October 2004 when he intervened to stop a gang attacking his friend Louis Colley. Of the eight people charged with his murder, just two, Sam Hallam and Bullabek Ring-Biong, 20, were convicted. Mr Hallam says that not only was he not a member of the gang that attacked Mr Kassahun, he was not even present when the attack, near Old Street underground station in east London, took place. He says he was playing football with a friend half a mile away.

The Independent reported last June that eight new witnesses have come forward to say that Mr Hallam was not involved. Now many of those witnesses have been interviewed by a team of 25 detectives led by Detective Chief Inspector Steve Tolmie of Thames Valley Police.

The decision to appoint a new investigating officer was taken last year, because the CCRC decided that every witness who gave evidence in the original investigation needed to be re-interviewed, and the original police notes re-examined – something it lacks the manpower to do. The secrecy was thought necessary to prevent the witnesses, who all live close to one another, colluding before they were questioned.

The CCRC also feared that witnesses would need to be interviewed under police caution – powers they lack – but this has not happened.

DCI Tolmie's investigation has now spoken with all of the witnesses from the original trial, including two who gave statements naming Mr Hallam as one of the attackers during the investigation but subsequently withdrew those comments during the Old Bailey trial.

One girl told the court: "I was just looking for someone on the spot to blame," while a male witness said that Mr Hallam was "the only white boy I know from Hoxton, so I said it was Sam".

It is understood that the new investigation has turned up at least one new significant line of inquiry. During the original trial some witnesses mentioned that they had been told that "Sam" was involved. It is believed that the new inquiry team have discovered that this "Sam" is not Mr Hallam.

Mobile phone records, which were not sought by either the prosecution or defence in the original trial, would, Mr Hallam's legal team believe, prove his innocence. It is not known whether the CCRC investigation or DCI Tolmie's inquiries have been able to recover them.

Mr Hallam was sentenced to a spend a minimum of 12 years in prison, but because he will not admit to his crime he is only likely to be released if his conviction is quashed. Any parole attempt is likely to fail because without an admission the parole board is unlikely to accept that he has been rehabilitated.

While Sam's family welcomed the new investigation, they are frustrated at how long it has taken to materialise. Sam's campaign group submitted the new witness statements to the CCRC in February 2008, but his case was not allocated a case worked until seven months later. In February this year the CCRC decided a new police investigation should be launched, but it has still refused to set a deadline for when it will decide whether or not to refer the case to the appeal courts.

Sam's campaign is run by Paul May, the man who successfully campaigned to have the Birmingham Six and the Bridgewater Four freed. Mr May said: "This is a highly significant development. It is very unusual for the CCRC to order such an enquiry, but we are still frustrated at the amount of time this is taking. Sam effectively lost his teenage years when he was convicted – how much of his twenties will he lose before he is free?"

A spokesman for the Criminal Cases Review Commission said: "It is regular practice for the Commission to require the appointment of an investigating officer from an outside force for reasons of impartiality and independence. The appointment of an investigating officer from a force other than the Metropolitan Police should not be taken to imply that the Commission has concluded that there was anything wrong with the original investigation."