It has taken 14 long years, nearly 3,000 statements and the questioning of around 8,000 local residents, but the police investigation into the murder of Shamsuddin Mahmood was hailed as a triumph by officers and prosecutors.

Referring to a “callous” murder that shocked “not only the local community but people throughout Scotland”, Andrew Laing, the Prosecutor Fiscal for the Highlands and Islands, said yesterday: “Prosecutors and officers from Northern Constabulary were determined that justice would be done in this case.”

The killing of Mr Mahmood in 1994 was so unexpected that Alistair MacLeod, then the islands’ chief inspector, later admitted that his officers had never even drawn up contingency plans for a murder. Just three officers were on duty in Kirkwall that night, while those called to the scene included Edmund Ross, the local firearms officer, whose son Michael was yesterday found guilty of the killing.

Defending his force’s response time on that night, Mr MacLeod told the Orcadian newspaper: “The local team was under way in a very, very short time – within minutes. Everything that should be done was done and we reacted as quickly as we possibly could.”

Despite his attempt to put a positive gloss on the investigation, police were struggling from the start, thwarted by a failure to find the murder weapon, the absence of DNA or fingerprints and a lack of any clear motive.

Officers were flown in from Northern Constabulary’s headquarters in Inverness, while inquiries were carried out at every address in Kirkwall as well as in the Bangladeshi communities in London and Southampton.

In a personal appeal on the front page of the Orcadian, Detective Superintendent George Gough, the policeman in charge of the investigation, admitted on June 23 that year that his officers were baffled.

It was only after Ross’s father placed suspicion on his son by admitting that he had a box of ammunition of the same type and calibre as the murder bullet, that the circumstantial case against the 15-year-old began to come together.

Although police believed that they had their man, Ross’s refusal to confess despite hours of questioning and a lack of any single clinching piece of evidence meant that the case began to falter. A police E-fit picture of the main suspect, bearing a strong resemblance to Ross, also failed to provide a breakthrough. By September 8 the investigation had been scaled down to just five local officers.

A decision to charge Ross was not made for another 13 years, prompted by the 2006 “confession” of a local man who said that he had seen the teenager with a gun on the night of the killing. But the evidence of William Grant was far from convincing and Judge Lord Hardie told the jury that there was enough circumstantial evidence to convict without it.

The suggestion that the case against Ross was strong enough even in 1994 will lead many to question how effectively police did their job.

From killer to war hero

— Like many teenage boys, Michael Ross was fascinated by guns and the military. At the age of 14 he even asked his father for a self-loading rifle for Christmas

— His interest led him to join the Army Cadet Force in Orkney, where his skill as a marksman won praise from instructors

— It was a record of achievement that was continue after he joined Black Watch in Inverness in 1996. He was described as one of the finest shots in his intake

— Ross served at least one tour in Northern Ireland and one in Iraq, where, in 2005, he was praised for bravery under fire after his unit was targeted by suicide bombers

— His captain told the court that Ross was one of the finest soldiers he had ever commanded

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