The Arlene Fraser case is one of the most complex and challenging investigations ever undertaken by Grampian police.
On Wednesday Nat Fraser was again convicted of murdering his wife following a retrial. He'll serve at least 17 years behind bars.
The jury accepted that Nat himself did not kill Arlene - he had a cast iron alibi - but he did arrange for someone else to do it.
Alan Smith, a former detective who worked on the case, said: “[Who did it] would be speculation but I would think that it was someone who Nat could trust. Someone who would be loyal to Nat, rather than a stranger.”
Arlene’s mother, Isabelle said: “It’s a mystery to who this other person is. We have our own thoughts of someone else involved but obviously don’t want to say. But there must be another person who is free. Surely Nat Fraser should name them.”
Back in 2003, at the start of the original trial, three men were charged with Arlene's murder - husband Nat, fruit and veg salesman Glenn Lucas and farmer Hector Dick
Glenn Lucas was a close friend of Nat - who subsequently wrote a book about the case.
He died in 2006 still firmly denying any involvement.
In a sensational twist, Hector Dick turned Queen's Evidence against Nat and the charges against him Lucas were dropped.
During the retrial, Nat accused Hector Dick of murdering his wife but Mr Dick has always protested his innocence - while accepting he initially lied about buying and disposing of a car for Nat at around the time of Arlene's disappearance - and by the terms of their verdict, jurors made it clear they did not accept his claim that Nat had hired a hit man to kill his wife.
Mr Smith: “The essence of carrying out a paid murder is that it is done swiftly cleanly with as minimum contact involved with the victim as possible.
“So I thin if there was a hit man we would have found ourselves with a body on the doorstep.”
Grampian Police has refused to confirm whether they will actively search for Arlene's killer or indeed her body, which has never been found.
Her family believe only Nat knows the whole truth and he will take it to his grave.
Already his lawyers have confirmed they're considering grounds for an appeal.
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