Family seeking answers 16 years after Colin Marr's death

And the family of Colin Marr, who was found with a single stab wound in his home in July 2007, believe that's removed a major obstacle to re-opening the cold case and carrying out a proper investigation to establish the truth of his death.

His mum, Margaret, and step-father Stuart Graham have never accepted the official version that he committed suicide and highlighted the "repeated failures" of the authorities who they say have mishandled the case, and then lied to cover up their mistakes, from the very start.

They were also highly critical of Professor Sue Black's opinion on the location of the fatal wound and the force needed to deliver the blow, which supported the police version that the 23-year-old killed himself.

Colin Marr died of a single stab wound on July 10, 2007. (Image: Colin Marr Memorial Trust)

However, she has now stated that opinion, given to police officers from Strathclyde who were instructed to carry out a re-investigation in 2012, can no longer be relied upon due to additional information that "was not presented at the time".

Mr Graham believes the verdict of suicide should now be "off the table".

The Crown Office and Procurator Fiscal Service (COPFS) have confirmed that a forensic and pathology review of the case, that was ordered last year, will be widened in scope to take the new information from Professor Black into account.

This week Colin's step-dad, Stuart Graham, told the Press: "The Sue Black report seriously undermined the outcome of the Strathclyde investigation and was in conflict with the fatal accident inquiry (FAI) findings."

He added: "The fact that there is a full forensic and pathology review, in theory, should be significant as there is a significant barrier now removed."

Colin, a 23-year-old mortgage advisor and Dunfermline Athletic fanatic, was originally from Inverkeithing and lived with his fiancee, Candice Bonar, at Johnston Crescent in Lochgelly.

A 999 call was made on the evening of July 10, 2007, the ambulance arrived at 8.20pm and attempts to revive him failed. 'Life extinct' was certified by paramedics around 9pm.

He died of a single stab wound, a kitchen knife was found several feet away, and he had also suffered a blow to the head.

READ MORE: Family call for public inquiry into Colin's death

The location of the wound is highly significant as experts have said that it would be unlikely someone would be able to stab themselves with sufficient force to penetrate the sternum and pierce the heart - which is what happened, according to the pathologist who carried out the post-mortem.

Colin's mum, Margaret, and step-dad Stuart Graham do not believe that the 23-year-old took his own life. (Image: Newsquest)

Leading forensic pathologists such as Dr Nat Cary, who worked on the case of Soham child murderer Ian Huntley and assisted the families of those killed in the Hillsborough Disaster, said that fact meant the death should have been treated as a homicide until proven otherwise.

His report said: "In my opinion it is both possible and plausible that this was a stab wound inflicted by a third party.

"Forensic pathology is not capable of making an absolute distinction. However, this case should have been and should continue to be pursued as a case of potential homicide."

Ms Bonar has never wavered from her position that, after an argument in which she said she was leaving him, a distraught Colin had plunged the knife into his own chest.

She had travelled back from Australia, where she now lives, to attend the FAI in 2011.

After it she said: "My name is cleared. I have always been honest and declared my innocence throughout this heartbreaking nightmare.

"What Colin did, he did to himself and that's the truth."

READ MORE: Expert backs family's fight for justice

The FAI was inconclusive, as Sheriff Alastair Dunlop was unable to determine who was responsible for the fatal blow, and police officers from Strathclyde were instructed to re-investigate the case the following year.

They consulted Professor Black - a forensic anthropologist who is now Baroness Black of Strome - who contradicted the findings of the post-mortem and FAI by suggesting the knife had instead gone through soft tissue, which would not have required as much force and supported the police view that Colin killed himself.

In a letter to Mr Graham the COPFS said they were not aware of the comments attributed to Baroness Black, until they appeared in another newspaper, but have now "instructed the police to carry out some further work as a result".

This will then be considered by crown counsel.

READ MORE: 'The way this case was handled was diabolical'

They added that the forensic review is being carried out in phases, further scientific work has been done in relation to fingerprint evidence and a report on the findings will conclude the first phase.

The letter continued: "COPFS officials will then meet with the police and scientists to discuss what, if any, further work ought to be done.

"The review of pathology evidence is also still ongoing. We hope to have a report of this review in the early part of the new year."

Mr Graham had previously told the Press: "This is not about who killed Colin but asks the question, why did they not want to know who killed Colin?

"The continued distortion of evidence to ensure protection of their own has been the constant barrier to effective justice."