Connor Gibson, 20, was convicted of attacking his sister Amber in woodland in Hamilton, South Lanarkshire, on 26 November 2021.

He removed her clothing, sexually assaulted her with the intention of raping her, inflicted blunt-force trauma to her head and body, and strangled her.

Gibson denied the charges against him but was found guilty after a 13-day trial at the High Court in Glasgow.

Amber was reported missing on the evening of Friday 26 November and her body was discovered in Cadzow Glen at about 10.10am on 28 November.

Gibson was arrested three days later on 1 December and, the day before his arrest, posted a chilling tribute to the sister he murdered, writing on Facebook: "Amber, you will fly high for the rest of time. We will all miss you. Especially me. I love you ginger midget. GBFN (goodbye for now) X".

The forensic pathologist who carried out the post-mortem examination on Amber's body told the court she was found covered in mud and the cause of death was "compression of the neck".

Jurors also heard other forensic evidence that "widespread blood staining" on Gibson's jacket was compatible with Amber and his DNA was also found on her shorts, worn as underwear, which had been "forcibly torn" off.

The court heard Gibson, also known by the surname Niven, did not seem emotional as he spoke to his and Amber's former foster father, Craig Niven, on the day her body was found.

Giving evidence, Mr Niven had said he would not leave the siblings in each other's company because they were "not a good mix".

Mr Niven and his wife had fostered the siblings since Amber was three and her brother was five. The couple were granted permanent care of the siblings a few years later.

At the time of Amber's murder, Connor was living at the Blue Triangle homeless hostel in Hamilton while Amber was at the town's Hillhouse children's home.

Mr Niven told the court he had not heard from his former foster son during Amber's disappearance but, in a call on the day her body was discovered, Gibson told him the pair had "fallen out" when they saw each other two days previously.

Jurors also heard from Peter Benson, of Police Scotland's cyber crime group, who examined a phone found where Gibson was living.

It showed that on 27 November at about 12.34am, the phone's user wrote to a Snapchat group with five recipients: "I'm really going to need you guys help with something when yous come back. I'm being serious."

Around 40 seconds later the user messaged Amber on the app: "Are you ok?"

The user then told the group chat at approximately 1.33am: "nvm (never mind) it's all good."

The search history obtained from the phone also showed the user searched "how to get nosy police officers to stop monitoring your phone" at 11.38pm.

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Iain Currie, manager of Hillhouse children's home, told the court he spoke to Gibson at about 9pm on 26 November after he called to speak with his sister, but noted him appearing "sharp" on the phone after making no greeting.

Also on trial was Stephen Corrigan, 45, who was found guilty of attempting to defeat the ends of justice by intimately touching and concealing Amber's body after discovering her at some point in the following two days, instead of contacting the emergency services.

Corrigan, said in court not to be known to Gibson, also denied the charge and had lodged a special defence of alibi.

His father, William Corrigan, 79, told the court his son was at his home in Blantyre, South Lanarkshire, that weekend after a fall on ice left his arm in a sling, and denied lying to protect him.

The court heard Corrigan told police he was at a "complete loss" to explain why his DNA was found on 39 areas of Amber's body, including her breasts, buttocks and thighs.