A man has been found guilty of sexually assaulting and murdering his 16-year-old sister in a park in Hamilton.
Amber Gibson's body was found in Cadzow Glen on 28 November 2021, two days after she was last seen.
Connor Gibson, 20, strangled Amber then got rid of clothes he had been wearing and called the children's home Amber was staying at to pretend she was still alive.
Another man has been found guilty of interfering with Amber's body.
Stephen Corrigan - who was unknown to both Amber and Connor Gibson - found her body, but rather than alert police, he inappropriately touched her and then concealed her remains.
Amber's body was discovered in Cadzow Glen on Sunday 28 November, hidden in bushes and branches. Her body was covered in mud, and her clothes were found nearby.
Gibson was arrested three days later on 1 December. The day before his arrest, he posted a tribute on Facebook to the sister he murdered.
During the trial at the High Court in Glasgow, the jury heard that Gibson had removed Amber's clothes and assaulted her, repeatedly inflicting blunt force trauma to her head and body as well as compressing her neck with his hands.
In his closing statement, prosecutor Richard Goddard KC told the jury Amber Gibson was "appallingly" murdered by the brother she must have trusted. He named 21 different circumstances which linked Gibson to the murder and sexual assault.
Connor Gibson had denied all the charges against him.
The 13-day trial heard that the siblings were fostered from the age of three and five by Craig Niven and his wife Carol. The couple were granted permanent care of the siblings a few years later.
Amber left their care in 2019. Mr Gibson left after he turned 18 in 2020.
Mr Niven had told the court the siblings could not be left in each others' company as they were "not a good mix".
He said that he spoke to Connor Gibson on the phone in the days after Amber's body was found.
According to Mr Niven, Gibson said he argued with his sister before seeing her later that Friday night.
At the time of Amber's murder, she was living at the town's Hillhouse children's home.
Connor was living at the Blue Triangle homeless hostel in Hamilton. A police officer told the court that items of stained clothing had been found in a bin there.
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.
It emerged during Amber's murder trial that she had suffered another assault earlier in 2021.
In an entirely separate case it was revealed that in the June before her murder, Amber was raped by a man called Jamie Starrs.
Court documents also show that Amber and Connor Gibson's biological father, Peter Gibson, sexually assaulted two young boys and assaulted and raped a woman.
These crimes were committed between 2001 and 2008. He was convicted in January this year.
Police Scotland called the inquiry "traumatic and harrowing" for the officers involved, as well as for Amber's friends and family.
Det Ch Supt Paul Livingstone said: "It is hard to imagine how difficult this has been for Amber's family and friends and our thoughts very much remain with them.
"I hope this conviction brings them some degree of comfort. The actions of both Gibson and Corrigan leaves them beneath contempt."
He said the investigation was "complex and challenging" and had relied heavily on the expertise of forensic officers.
The siblings' foster parents issued a statement following the verdict.
It said: "When they arrived at our home, Amber was three and Connor aged five. Connor stated: 'We are safe' - they were until he took the safety away."
They described Amber as the "most giving, caring, loving, supportive and admirable person" who had a love of art and singing and an "amazing outlook on life" despite the suffering she had experienced.
The couple commented on "how much Amber and Connor have been let down throughout their lives by the system".
"We now have one daughter buried in Larkhall Cemetery and another child in prison," they said. "Life will never be the same."
Judge Lord Mulholland sent jurors out to consider their verdicts on Tuesday morning. They returned just before 15:00.
Lord Mulholland told Connor Gibson he would receive a life sentence.
He said that the last thing Amber would have seen was her brother strangling her, and told him: "You will pay a heavy price for that."
He told Stephen Corrigan he had committed "horrific crimes" and that his DNA "told the story".
The two men will be sentenced on 4 September at the High Court in Livingston.