A knife was found on the beach opposite the house where Alesha MacPhail was last seen, a murder trial has heard.

Peter Morrison, a volunteer member of the coastguard who carried out a search of the shoreline, told the High Court in Glasgow on Friday that he discovered the blade.

He said it was "clean", explaining that it would have been in the sea but was left exposed by the receding tide.

A 16-year-old, who cannot be named for legal reasons, has gone on trial charged with raping and murdering six-year-old Alesha.

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

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

Mr Morrison, 39, from Rothesay, said he was called out to carry out a shoreline search at 6.55am.

Opposite the house where Alesha had been staying, he found "what looked like a kitchen knife".

Mr Morrison said he did not touch the knife, but noted its location before continuing to search for Alesha. He later told police, who cordoned off the area.

The court also heard from police sergeant Anthony Hannah, who said he arranged for photos to be taken and the knife to be recovered.

He also said he threw a separate item of evidence in a skip believing it was not relevant to the murder inquiry.

He said the black hooded top, found by a dog walker on the beach, was later retrieved on the instruction of detectives.

The court also heard on Friday that the 16-year-old accused sent a video of himself to friends with the message: "Found where the murderer was hiding."

Giving evidence, 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.

The witness said she thought it was a "bad joke" but she later told the police when it emerged an arrest had been made in the murder inquiry.

She said he also sent messages to the group "saying what he thought could've happened" and how Alesha could "have got out the house without anybody noticing in the house".

She agreed other people in the group were contributing "gossip, rumour and speculation".

The court also heard from another friend of the accused, who said the boy had messaged her at around noon on July 2 asking if she had seen anything and if she had walked her dog that morning as she normally went where Alesha's body was found.

She said: "He started to get anxious and said the police were going to blame it on him."

He told her police always blamed him for things that happened in that area and he was "going to get arrested".

She said she tried to calm him down and "brushed it off" at the time as she knew he suffered from anxiety but later told police.

The witness also showed police messages he sent her in 2017, saying he "might kill one day for the lifetime experience".

Other messages said he would probably "stalk her" and "go into her room".

She asked him the chances of getting away with murder with a good plan and he replied: "Well if it was a good plan then 100%."

She later messaged: "I'm glad I'm not at the top of your hit list."

He replied: "No one is."

The teenager agreed these were theoretical exchanges where she brought up the subject of murder and at the time caused her no concern, saying they both had a dark sense of humour.

The trial went on to hear from another friend, who found the boy feeling "depressed" at his house in the early hours of July 2.

The 16-year-old had earlier had a party there.

This boy, also 16, recalled: "He was not that good, he was not in a good frame of mind.

"He said that he had a family problem - about his mum drinking.

"He said he was depressed and was thinking about harming himself.

"I was worried for him. I offered to stay with him or have him at mine."

The witness later messaged the boy, who claimed he was "okay now".

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.