New scientific breakthroughs could hold the key to tracing the gunman who shot Alistair Wilson on his doorstep in cold blood.
Officers from across Scotland are currently poring over every piece of evidence gathered in the past 10 years in the hope of finding the crucial clue that will finally trap the killer.
Witnesses could be interviewed again in the hunt for the gunman, police chiefs revealed yesterday, as they underlined their commitment to solving the crime which shocked a nation.
And a £5,000 reward for information leading to a conviction has also been renewed by Crimestoppers in the hope of flushing out the vital scrap of information that could unlock the mystery.
Yesterday, the detective in charge of the major review said he was optimistic that the “highly unusual and highly complex murder” could still be solved.
Detective Superintendent Gary Flannigan said the determination to find Mr Wilson’s murderer was “undiminished”.
The banker’s family also made an emotional plea for information about the callous killing yesterday, as a new image of the 30-year-old father-of-two was released.
The photograph shows Mr Wilson and his older sister Jillian at Nairn beach in 2003 while she was home in Scotland from Australia.
It was the last time she saw him alive.
Urging anyone with knowledge to come forward, Mr Wilson’s widow Veronica, his parents Alan and Joan and his sister, said they feared that the killer could strike again.
Mr Flannigan said the “homicide governance review” involved officers going back over “every box, every message we received, every piece of intelligence and building a case”.
The process, which started eight weeks ago, is expected to be completed within the next few weeks.
It is the first time that every piece of evidence has been re-examined – although there have been five previous reviews of the investigation.
At the conclusion of this latest phase, the team will decide what lines should be followed up as part of the inquiry.
Mr Flannigan said science had moved on dramatically in the past 10 years and new forensic techniques could be used to re-examine evidence in the case.
Among the items under examination are the gun which was retrieved from a nearby drain near the crime scene 10 days after the murder, and a cigarette butt found at the scene.
A DNA profile was extracted from the cigarette end but it was never identified, said Mr Flannigan.
“Science has developed beyond belief in 10 years and it is through that type of process that we would expect to make some type of progress,” he added.
“We appeal to members of the public, not just in the local area or Scotland, but anywhere that they are potentially listening to this.
“If you have any information whatsoever, then I would ask you to get in touch.”
He added: “While the information coming to us has slowed down, I know that someone somewhere knows exactly how and why Alistair was shot.
“Unsolved homicides are never closed, they remain open in the hope that the vital piece of evidence surfaces to help the investigation to a conclusion.”
Chief Superintendent Julian Innes, north divisional commander, worked on the original investigation and expressed his frustration that the killer was still at large.
He said: “Nobody has forgotten about this in Police Scotland. We are determined to solve this case.
“What I would say to the communities of the Highlands and islands is, think again as we approach the 10th anniversary. Just have a think.
“Is there anything that you haven’t told us? Anything that you have reflected on since 2004 that you maybe think we should know?”
Anyone with information should contact police on 101 or Crimestoppers on 0800 555111.