A boy accused of murdering six-year-old Alesha MacPhail has said her dad's girlfriend had "murder on her mind".

The 16-year-old denied murdering Alesha or having sexual intercourse with the child, claiming he had never met her before and didn't know her name until everything had happened.

He claimed he had sex with Rab MacPhail's girlfriend, Toni McLachlan, on the shore on the night Alesha went missing.

The teenager then went on to say Ms McLachlan had "murder on her mind", blaming the 19-year-old for the killing.

The youngster claimed he gave his black hooded Nike top to Toni after they had sex because she said she was cold.

The accused said he then went home before realising he didn't have his phone.

He went out in just shorts and no shoes to look for it, carrying a T-shirt.

The teenager said the path was "stoney" so he came back home to put shoes on and get a torch.

A 16-year-old girl said Alesha going missing was discussed in a Snapchat group chat of around 25 friends on Monday, July 2 last year.

She said the accused sent a video of himself filmed in a mirror showing his top half but not his face to the group, followed by the message.

Responding to that in court, he said: "Everyone was talking about who could have done it.

"My name was mentioned. I didn't want to take it to heart and thought I'd build on it."

Alesha was reported missing from her grandparents' home on the Isle of Bute at 6am on July 2 last year.

Her body was found in a wooded area of the island a few hours later.

Earlier on Tuesday, the trial heard DNA belonging to the boy accused of murdering the six-year-old was found on her body after she died.

Stuart Bailey, a forensic scientist with the Scottish Police Authority, said DNA of the 16-year-old was found on various parts of Alesha's body, including intimate areas.

The jury heard 14 samples matched the accused, meaning it was highly unlikely this was transferred through a third party.

He said an explanation for this was intercourse but the defence suggestion that the accused's was "planted" there was scientifically possible.

Questioned if the accused's DNA could have been found on Alesha though secondary transfer from a third party, Mr Bailey said: "I can't rule it out but I find it highly unlikely given the amount of DNA attributed to [the accused]."

The teenage murder accused 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, on July 2 last year.

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 trial continues.