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

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]."

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.

A knife which was discovered on the beach opposite where Alesha MacPhail was last seen had no blood on it or DNA present.

Jogging bottoms which were recovered from the shore having been in the sea had partial traces of DNA which matched the accused.

A black hoodie which was heavily salt stained was also discovered on the shore had no DNA.

The jury heard on Monday a Google search "how do police find DNA" was made from the phone of a boy accused of murdering Alesha the day after she was found dead.

The court heard the search led to a page being accessed shortly after 12.30am on howstuffworks.com under "collecting DNA evidence".

Cyber crime team leader Peter Benson said this would be "something you type in".

The 16-year-old has lodged a special defence of incrimination, blaming Toni McLachlan - the girlfriend of Alesha's father Robert MacPhail - for the killing.

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.