Murderer Norman Duncan stabbed grandmother Margaret Robertson to death in drug-fuelled knife attack in Aberdeen

A man who murdered a grandmother in a crack cocaine-fuelled knife attack has been jailed for life.

Norman Duncan stabbed Margaret Robertson, 54, at least 25 times during the fatal assault at her Aberdeen home.

A judge told the 43-year-old: “This was a sustained and merciless attack inflicted upon a defenceless woman in her home.”

At the High Court in Edinburgh, Lord Harrower ordered the murderer to serve 20 years in prison before he is eligible to seek parole.

The judge warned Duncan: “This does not mean you will be released automatically at the end of that period.”

He said his date of release, if any, would depend on the view taken by the parole board of the risks he posed to public safety.

Duncan had denied murdering Ms Robertson or Fullerton, who was known as Meg, on September 25, 2019.

However he was found guilty of the murder during which he struggled with his victim, sexually assaulted her and repeatedly stabbed her in the head, neck and body with a knife.

Duncan had originally stood trial for the murder last year but proceedings were brought to a halt because of his mental health at the time.

The court heard that he had been abusing psychoactive drugs while in prison which left him unfit for trial. He was subsequently placed in the high security state hospital at Carstairs before being returned to the prison system.

Defence solicitor advocate Iain Paterson said Duncan was diagnosed with a schizoaffective disorder and was taking antipsychotic medication. He said the father-of-two has struggled with drugs since the age of 26.

The court heard that the murder victim was left lying near naked in her flat where she was found by a friend who thought it odd to find the front door to her home unlocked. He alerted emergency services.

Jurors heard that on the day of the killing he made three trips to the block of flats where his victim resided in search of the highly addictive narcotic crack cocaine.

Duncan twice sourced the Class A drug from another resident at the flats but claimed he failed to get more of it on his final visit. He later told police that he could spend up to £100 a day on crack if he had the money.

Between visits he changed out of a Nike tracksuit and donned an Under Armour tracksuit. He told detectives: “The reason I changed my tracksuit is because I got a brand new tracksuit.”

But the Crown maintained that Duncan had another motive for switching his clothing after visiting the flats.

Advocate depute Bill McVicar said that during the 109 minutes Duncan spent at the property during an initial visit he had “ample time to source and collect his crack cocaine” and carry out the murder.

The prosecutor said: “If there was no blood on his clothing there was no good reason for him to change his clothing or his shoes before returning to Promenade Court to buy more drugs.”

The court heard that DNA matching Duncan was found under his victim’s finger nails and she was seen to have sustained defensive injuries as she tried to protect herself. Other forensic evidence also pointed to Duncan as the murderer.

The cause of death was certified as multiple stab wounds to the neck and face.

When Duncan was detained by police he was initially found to be unfit for interview.

He originally faced further charges of possessing cocaine and attempting to defeat the ends of justice by changing out of blood-stained clothing and trainers and washing them, discarding a knife, hiding from police and providing false details to officers.

The Crown withdrew those charges during the trial and he was acquitted on them.