A blue envelope handed to Nairn banker Alistair Wilson minutes before he was shot dead on his doorstep was empty, police have revealed.
The father-of-two was murdered 13 years ago today, but despite a huge investigation his killer has never been found.
Yesterday, his widow Veronica said it would mean the “world” to her family if the shooter was finally brought to justice.
Meanwhile police revealed new details of their investigation – and said they could not rule out the theory that Mr Wilson’s death was a case of mistaken identity.
Mr Wilson was handed a blue envelope, with the name Paul on it, on the doorstep of his home.
Detective Superintendent Gary Cunningham yesterday confirmed it was empty, and said he “can not rule out” theories on the envelope which he says could include the killer deploying a distraction technique, expecting something to be put inside the envelope, or a case of mistaken identity.
He added: “My appeal to the public is that someone out there knows exactly why there was an envelope and if we can get that information we can focus on the motive.
“Allegiances change (in 13 years) and we can only hope that someone might come forward.”
He also revealed that a gun identical to the murder weapon, a German-made Haenel Schmeisser 6.35mm, was found in Nairn during a house clearance last summer.
Police said it is not linked to the case but have called for anyone who owned an identical model and passed it on – or had one stolen – to come forward.
Det Supt Cunningham said about 40,000 of these guns were made between 1922 and 1930, but only 13 have ever been recovered in the UK – just three in Scotland.
In a statement, Mrs Wilson echoed the appeal for anyone with information to come forward.
She said: “It would mean the world to us to have Alistair’s killer brought to justice. As a family, it has been difficult to understand why someone would do this to Alistair and it has been a dark shadow over us for the past 13 years.
“Alistair was a loving, caring husband and father and nothing will ever change that. We cherish the time we had together, which for our boys was cruelly short.
“We will always remain hopeful that the person who killed Alistair will be caught and I would urge anyone who has information to come forward.”
Mr Wilson had been reading bedtime stories to his two sons on November 28, 2004 when his wife answered the door to a stocky man, aged 35-40, who asked to speak to him by name.
Mr Wilson went downstairs and had a short discussion with the man before returning, bewildered, with the envelope. He went downstairs to see if the man was there and was shot three times.
During the investigation, police have spoken to nearly 14,000 people, taken 3,500 statements and conducted door-to-door inquiries at more than 1,000 addresses in Nairn.
About 700 productions have been assessed for any evidence and CCTV has been collected from 670 different sources.
Det Supt Cunningham said the advent of DNA24 now allows police to obtain DNA profiles from items which, when previously tested, did not produce a profile. He said that this is a key line of inquiry as they are reviewing relevant items to the case.