Aaron Campbell, 16, is beginning a life sentence with a minimum of 27 years for snatching Alesha from her bed, raping her and dumping her body on the Isle of Bute last summer.
Sentencing Campbell at the High Court in Glasgow on Thursday, judge Lord Matthews said the “callous, calculating” teenager had shown not a flicker of emotion during the nine-day trial that saw him convicted.
There was further turmoil for Alesha’s family in court as Campbell’s lawyer revealed he had since admitted the crime, telling psychologists that when he came across Alesha sleeping in her bed “all I thought about was killing her”.
Alesha’s mother Georgina Lochrane, 24, told the Daily Record: “A life sentence should be a life sentence. He should have no human rights and doesn’t deserve anything because he is inhuman.
“I will do whatever I can to make the parole board see that that can’t be released back into society.”
Ms Lochrane, from Airdrie, told the paper: “He doesn’t deserve to breathe the same air as my family. It rubs salt into our wounds the fact he is still alive and she isn’t.”
Alesha was a few days into a summer holiday with her father and grandparents, staying at the home they shared on Bute in the Firth of Clyde.
Father Robert MacPhail, who split from Ms Lochrane after Alesha was born, told the trial how he put his daughter to bed on July 1 and was woken the next morning by his frantic parents Calum MacPhail and Angela King saying she was missing.
A few hours later her naked body was found dumped in nearby woodland, with a post-mortem examination recording more than 100 injuries.
Detectives recovered clothes and a knife from the area, and further evidence came from Campbell’s own mother, who provided CCTV footage which showed her son coming and going several times in the early hours of July 2.
He had been drinking with friends at his house and wanted cannabis, so went to the home of Robert MacPhail who had sold him the drug in the past.
There he found the door unlocked and went into the first room on the left where Alesha lay sleeping.
He told psychologists Alesha was drowsy but wakened a bit when they went outside, and he gave her his top because she was cold.
She asked who he was, and the killer told her he was a friend of her father’s and was taking her home.
Campbell was said to be “mildly amused” in the days following the murder that he had not yet been arrested.
He told how he was “quite satisfied” with the murder and had struggled to contain his laughter during the trial.
Lord Matthews told Campbell at his sentencing: “You are completely lacking in victim empathy, the social worker noting your cold, calculating manner.
“The only sentence I can impose on you is detention without limit of time.”