Ten years after Arlene Fraser, still wearing her nightdress, waved her son and daughter off to school from the doorstep of their home in Elgin in Moray, her disappearance remains Scotland's most baffling murder case.

By the time the children returned later that day, April 28, 1998, their mother had vanished.

Today, the circumstances surrounding Mrs Fraser's disappearance are still unknown and the case remains largely a mystery, though no one doubts that she was killed.

In 2003 Nat Fraser, Mrs Fraser's estranged husband, was found guilty of hiring a hitman to murder his wife. But the emergence of new evidence after his trial cast doubt on his conviction.

After a two-week hearing at the Criminal Court of Appeal last November judges are reportedly expected to issue a decision about Mr Fraser next week.

Yesterday Mrs Fraser's family gathered in Elgin to mark the 10th anniversary of her disappearance.

The private ceremony was attended by Hector McInnes, her father, Isabelle Thompson, her mother, Carol Gillies, her sister, and, it is believed, her two children, who have been living with their paternal grandmother, Ibby Fraser.

Mrs Fraser's family have repeatedly asserted that she was murdered by Fraser as she would never abandon her children.

The couple's marriage had been in trouble and Mrs Fraser was seeking a £250,000 divorce settlement. Just three weeks before she vanished, Fraser tried to strangle her. He was convicted of killing his wife, whose remains have never been found, after one of the largest and most complex investigations ever mounted by Grampian Police.

Fraser, a fruit and vegetable wholesaler, was charged with conspiracy to murder, along with two co-accused, a local farmer, Hector Dick, and a businessman, Glenn Lucas.

The trial of the three at the High Court in Edinburgh in 2003 took a dramatic turn when charges against Mr Dick and Mr Lucas were dropped.

Mr Dick then turned Queen's evidence, and described how Fraser had told him he had hired a hitman to kill his wife. Mr Lucas, who died in September 2006, continued to defend his friend, writing a book on Mrs Fraser's disappearance, Murdered Or Missing?, which speculated that she had left Elgin of her own free will.

On January 30, 2003, Fraser was found guilty of murdering his wife. He collapsed in the dock as he was sentenced to at least 25 years in prison, but just three years later he was freed on bail after new information. Prosecutors had alleged during the trial that Fraser placed his wife's engagement, wedding and eternity rings in the bathroom of her house several days after she vanished, proving that he had access to her body.

However, two police officers later insisted they had seen the rings on the night Mrs Fraser was reported missing, leading Fraser's lawyers to argue during an appeal last November that he had suffered a miscarriage of justice.

Typically, in a case that has had more twists than an Agatha Christie novel, the appeal hit complications when it was revealed that the two police officers had not only been interviewed by Fraser's original defence team, quashing concerns that their evidence had been withheld, but also that they had failed to mention the rings.

After the two-week hearing, judges sent Fraser back to jail while they considered their decision, which is expected next week.

Senior legal sources told The Times last night that Fraser is unlikely to win his appeal. One source said: “His appeal should be successful, but it is not going to be. The judges will take the view that the rings are important, but the other evidence against him is very strong. I am absolutely certain he will stay in jail.”

Mrs Fraser's family hope the appeal is rejected. Mrs Thompson said: “If Nat Fraser walks free, it will be because of some loophole. I hope they leave him where he is. Let him rot there.”

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