The unanswered questions: why did he do it and was it a paid hit?

Usually, a trial will allow fact to emerge from the speculation and supposition pedalled in the wake of a notorious crime. But then there are rare cases like the Leslie Cumming attack.

From a very early stage in the trial, the tone was set. A senior detective in the investigation explained the standard procedures that had swung into place immediately after police received the report of a serious assault in the unexpected locus of Edinburgh’s affluent Murrayfield district.

“In simple terms, you were trying to find out what happened, and why,” suggested the prosecutor, Lesley Thomson, QC.

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“That’s correct,” said Detective Sergeant Bryan Burns.

“Do you always find out the why?” asked Ms Thomson.

“Not always, no,” he replied.

The jury heard Mr Cumming, deputy chief executive of the Law Society of Scotland, had been in charge of a team of inspectors who carried out regular checks on the books of law firms up and down the country.

Those were the people charged with weeding out any rogue solicitors. Could they have been getting too close for the comfort of a particularly desperate lawyer?

It was never spelled out as a possibility in the evidence, but that was certainly a theory at the time Mr Cumming was slashed and stabbed in the darkness of a winter’s evening in a lane behind his home.

Fortunately for the Crown, as Ms Thomson stated more than once to the jury, motive was not one of the things that needed to be proved for a conviction.

The best that could be offered was the evidence of a former workmate who had given police a statement to the effect that Graham had confessed to him.

“I worked at Wembley Stadium in January 2006,” said scaffolder Nicholas Wells, 33. “Rob [Graham] started a few weeks after me. He told me around this time he had done a judge in in Edinburgh, having jumped out some bushes at him. I can recall him telling me the guy from the BMW paid him £10,000 to do the job and told him to give the guy a good working over.”

Who was the guy from the BMW? Why had he paid £10,000 for the job? Why was “the judge” to be given a good working over? If the jurors asked themselves those questions, they were left searching for answers.

There had been an early, breakthrough when scientists identified DNA in scrapings from under Mr Cumming’s fingernails. But the trail remained cold until spring 2009 when a motorist was detained for a drink-driving offence in the south of England. A DNA sample was taken and the database flagged up a match with the DNA in the unsolved Leslie Cumming inquiry in Edinburgh.

Early on the morning of 10 June, 2009, detectives raided a house in Pilton Avenue, Edinburgh, and found a pregnant woman and her two children, but there was no sign of her partner and the children’s father, Robert Leiper Graham.

Martial arts enthusiast Graham was traced to a remote part of Western Australia, and extradition proceedings were started. In February this year, officers from Lothian and Borders Police travelled to Sydney, a handover took place at the airport and Graham was flown back to Scotland.