Connor Gibson, 21, was found guilty of attacking his sister Amber Gibson in woodland in Hamilton, South Lanarkshire, on November 26 2021, removing her clothes, sexually assaulting with the intention of raping her, inflicting blunt force trauma to her head and body, and strangling her.
He will be sentenced at the High Court in Livingston on Monday.
Following the 13-day trial at the High Court in Glasgow in July, Judge Lord Mullholland told Gibson he could expect a lengthy sentence for his crimes.
Amber, 16, was reported missing on the evening of November 26 and her body was discovered in Cadzow Glen in Hamilton two days later on November 28 at 10.10am.
Gibson was arrested three days later, on December 1, and, the day before his arrest, posted a chilling tribute to the sister he had 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.”
During the trial, the court hear how evidence from forensic pathologists showed Amber had died as a result of compression of the neck.
Also due to be sentenced on Monday is Stephen Corrigan, 45, who was found guilty of attempting to defeat the ends of justice and breach of the peace 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.
When Gibson was convicted, the former foster family of both siblings said in a statement that Amber was “the most giving, loving, supportive and admirable person”, and their life will “never be the same again”.
The family said: “She kept us on our toes and had the most amazing outlook on life consider the suffering she had experienced.”
The statement continued: “When they arrived at our home – Amber aged three and Connor aged five – Connor stated: ‘We are safe now’.
“They were until he took her safety away.”