WARNING: This article contains information some readers may find distressing.

A pathologist has told a murder trial that Alesha MacPhail was smothered to death and suffered 117 injuries.

The High Court in Glasgow heard that the six-year-old suffered "catastrophic" injuries, some more severe than pathologist Dr John Williams had ever seen before.

A 16-year-old has gone on trial charged with murdering Alesha on the Isle of Bute in July last year.

The court heard on Thursday that she had suffered multiple bruises and scratches to her face and neck, in addition to internal bruising.

The injuries were said to be consistent with being smothered and gripped by the neck.

The court was shown graphic images of the girl's injuries, which judge Lord Matthews warned were "distressing".

Prosecutor Iain McSporran asked Dr Williams: "You have carried out many post-mortems on victims of crime, including children.

"Have you ever seen anything of this sort to the private parts?"

The pathologist replied that he had not.

The doctor added that Alesha's feet were uninjured, which were consistent with being carried to the murder scene.

He added that the bleeding and bruising indicated that she was alive when the injuries were inflicted.

The teenage murder accused, who cannot be named for legal reasons, has pleaded not guilty at the High Court in Glasgow.

His legal team, led by QC Brian McConnachie, have lodged a special defence on his behalf, claiming the crime was committed not by him, but by Toni Louise McLachlan - the girlfriend of Robert MacPhail, Alesha's father.

On Wednesday, Ms McLachlan, 18, told the court she had no involvement in the killing, saying she loved Alesha "to pieces".

Prosecutors allege the boy was armed with a knife when he took Alesha from her bed at a house in Ardbeg Road in Rothesay, Bute.

It is claimed the boy then carried the schoolgirl to the site of the former Kyles Hydropathic Hotel on the island.

The indictment states he took off Alesha's clothes, shook her violently before placing his hands over her nose, mouth and around her neck.

The boy is said to have "applied pressure" to her face, inflicted injuries by "means unknown" with prosecutors alleging he went on to rape and murder Alesha.

The teenager also faces a separate charge of attempting to defeat the ends of justice.

The accused's mother also gave evidence on Thursday, telling the court she phoned police after spotting her son on home CCTV to eliminate him from their enquiries.

The woman, who can't be named for legal reasons, said her son had been drinking with friends at home in the hours before the six-year-old went missing.

The jury at the High Court in Glasgow was shown CCTV footage she believed showed her son leaving the house twice, but then returning during the early hours of July 2 last year.

The witness said she reviewed the footage to see if she could spot Alesha walking past on the morning she went missing and was surprised to see her son in the recordings.

She told the court: "My friend said I better tell the police. Obviously I did not think he had anything to do with it whatsoever.

"It was just to help the police. Maybe he had saw something that he would not tell me. It was to eliminate him from their enquiries basically."

The mum had earlier joined the hunt to try and find Alesha. She spoke to her son as the search was going on.

The woman recalled: "He was lying sleeping. I asked, 'have you seen this little girl - do you or your friends know anything?'.

"He said 'no' then just rolled back over."

After watching the CCTV, the woman then confronted her son about his movements.

She said: "I went into his room and said 'you went out again that night'. He was just like, 'I don't know, I think I might have been looking for my phone'.

"He just said that to me and I left him in his room.

"I had explained that they had found the little girl. I said, 'are you sure that you don't know anything about this?'. He said 'no'."

His mother later phoned police to "eliminate" her son from inquiries, saying: "Obviously I really didn't think he had anything to do with it whatsoever."

She described her son as "clever at maths", "well-liked" and said he had "lots of friends".

The boy later claimed to his mum he had gone out in the early hours to "buy weed".

Further CCTV footage showed the boy leaving the house for a third time at 4am. He was recorded shining a torch before running off.

The woman admitted speaking to her son again before he was arrested.

She said: "I was trying to explain to him that whoever done this, their DNA would be there.

"He was adamant he had nothing to do with it.

"There was no way they would find his DNA because he had been nowhere near this little girl.

"I was happy with that and sent him to his bed."

The woman was also shown a knife found on the shore at Bute during the murder probe.

She accepted it was "very similar" to knives found in a set at her home.

Welder Alexander McLachlan, 48, contacted police after watching CCTV footage from outside his Bute home in the early hours of July 2.

When asked about the clip in court on Thursday, he said it showed "someone walking as if carrying something" on the shoreline at 2.26am.

He added: "I presumed that it was someone carrying a child."

His sister-in-law Shari Strathie, 33, said CCTV from her home next door, also shown in court, featured a person carrying something on their front "with legs hanging down".

The trial continues.