PROSECUTORS are pursuing new "lines of inquiry" into the death almost 14 years ago of an Inverkeithing man.

Colin Marr, 23, died from a single stab wound on July 10, 2007, following a row with his fiancée, Candice Bonar, and it was initially treated as a suicide by police.

However, his family suspected he had not taken his own life and, after Fife police and the Crown Office admitted a series of failures concerning the handling of the case, began a long campaign to find out the truth.

Colin's step-dad, Stuart Graham, has gathered and handed over new material, including the findings of a report by leading pathologist Dr Nat Carey, that challenges the original police conclusion that it was suicide.

Dr Carey said it was "both possible and plausible" that Colin's injury was "inflicted by a third party" and questioned previous police reports on the location of the stab wound.

He also said Colin's death "should have been treated as a potential homicide" by the police.

Ms Bonar has always maintained her innocence.

In a letter to Scottish Lib Dem leader Willie Rennie MSP, who has helped the family for nearly a decade, Lord Advocate James Wolffe said: "Prosecutors have considered the material and have identified further lines of inquiry that they will pursue."

Mr Graham told the BBC the family "welcomes any further inquiries into the significant evidence shared".

He said: "A priority for us is that they quickly establish the actual wound location as outlined by Dr Carey, and the significant implications to the previous findings from fingerprint experts.

"There were other significant statements we have shared with Police Scotland regarding who went to the house and when, but no-one has asked for the contact information."

Colin, a Dunfermline Athletic fan originally from Inverkeithing, lived with Ms Bonar at Johnston Crescent in Lochgelly.

A Fatal Accident Inquiry (FAI) in 2011 heard evidence that he had been unfaithful and there was a "heated verbal exchange" during which Ms Bonar took off her engagement ring and threw it to the floor, telling him that the relationship was over.

She said as she prepared to leave, Colin had said he was going to kill himself.

Ms Bonar said when she returned to the living room, he had stabbed himself with a kitchen knife.

At the FAI, Sheriff Alastair Dunlop said: "I am left in the position of having to conclude that there is an insufficient evidential basis to allow me to say that one explanation for the fatal wound is any more likely than the other.

"In the result therefore, I cannot say that Colin Marr probably stabbed himself but nor can I say that he probably did not."

Fife police and the Crown Office produced reports previously that were critical of the original investigation into Colin's death and issued apologies to his family.

The Police Investigations and Review Commissioner also upheld 12 complaints over the force's handling of the case.

Earlier this year, Police Scotland and the Crown Office said they would consider any new material relevant to Colin's death.

Ms Bonar has been interviewed three times by the police and travelled voluntarily from Australia to appear in person and answer questions at the FAI into his death 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."