An urgent warning has been issued parents about the dangers of intense teenage relationships in an era of social media as an obsessed teenage boy was locked up for a minimum of 17 years for brutally murdering his ex-girlfriend.Even at the age of 16 Logan MacPhail controlled 15-year-old girlfriend Holly Newton’s life by stopping her going out with friends, demanding to know where she was at all times and changing her social media passwords.Holly once told her mother that MacPhail had warned her that ‘if he couldn’t have her, then nobody could’.The grieving mother said: ‘What we didn’t know is he meant it.’When Holly finally ended the 18-month relationship MacPhail stalked her and, despite police becoming involved, lured her into an alleyway when she was with another boy in January last year and savagely murdered her with a knife he brought with him. Holly Newton, 15, was stabbed to death in a vicious attack by her ex-boyfriend Logan MacPhail (then 16) after she ended their 18-month relationship Logan MacPhail has been jailed for murdering 15-year-old Holly Newton after he stalked her and stabbed her to death in January 2023 Holly’s mother Micala Trussler and her stepdad Lee arriving leaving Newcastle Crown Court todayMacPhail, now 17, was given a life sentence at Newcastle Crown Court today after being found guilty of murder.Passing sentence, Mr Justice Hilliard told MacPhail he was ‘filled with resentment and jealousy’ and had calculated the best place and time to launch his ‘vicious and brutal’ attack.He stabbed her 36 times to the head and body and Holly’s mother was stopped from holding her daughter in her arms for a final time ‘because of the horrifying condition she was in,’ the judge said.He declared: ‘What happened in this case should not have happened to any child or parent and no child or parent should be in fear that it might happen.’ After the hearing police said parents should be aware how toxic teenage relationships could become.Detective Sergeant Darren Davies of Northumbria Police, who worked on the case, warned parents of the dangers of unhealthy teenage relationships.He said: ‘It’s quite clear that as generations and technologies change, children are often far more involved in each other’s lives and their relationships are far more intense than they were when I was 14, 15 or 16.‘There needs to be parental, teacher and societal conversations around the intensity of teenage relationships to make sure that teenagers are aware of what’s healthy and what’s not, around contact, friends, passwords and access to each other’s social media and friend groups.‘Everyone is connected in some way these days. Parents need to be a lot more aware because these things can happen.’  Chilling CCTV footage captured the moment the jealous ex-boyfriend stalked 15-year-old Holly for 45 minutes undetected before luring her into an alleyway where he stabbed her to death  Footage shows the killer on a bus to Hexham on the day of the attack. He was so consumed with jealousy that he stabbed her to death when he saw her walking in town with another boy MacPhail, who was wearing a hat, arrived in Hexham on the afternoon of the killing and put on a face covering before following Holly and her friends  He followed them undetected for 45 minutesThe court heard how the evening before the murder MacPhail tried to see Holly at her home but was refused access. Police later picked him up and took him home.An arrangement was made for Holly to go with her mother to discuss the stalking problem with police after school the next day. However, Holly wanted to go out with friends and persuaded her mother to reschedule the meeting.Micala Trussler described this decision as ‘the biggest mistake of my life.’ In an interview with the BBC Ms Trussler said Holly felt sorry for MacPhail, who has autism, a serious speech impediment and learning difficulties, and did not know how to end the relationship.She added: ‘He was obsessed with her for a long time.‘He didn’t like her to go out. He didn’t want her to go out with her friends. He needed to know where she was all the time, even if she was just at home. He wanted to know what she was doing.‘He changed her passwords on all of her social media, so she was quite upset about that, because she couldn’t get into any of it. ‘There was just a lot of controlling behaviour going on.’  MacPhail, wearing a mask and hat, is pictured approaching Holly as she stands at a bus stop looking at her phone Holly suffered 36 injuries from the attack with a kitchen knife MacPhail had brought with him and the weapon broke in the attack He later told police ‘she was being too horrible’ as he tried to make excuses for killing the schoolgirl Chilling CCTV footage showed Holly talking to MacPhail at a bus stop in Hexham, Northumberland, moments before he persuaded her to go down an alleyway to chat.He then launched his deadly attack. Another boy who had been with Holly was stabbed as he tried to save the schoolgirl. The boy managed to alert members of the public who pulled MacPhail off Holly.They were commended for their bravery by the judge.The boy, who cannot be named for legal reasons, told the court before the sentence was announced: ‘What happened to me I wouldn’t wish upon anyone and I can’t imagine what Holly’s family are going through now.‘Whatever sentence Logan gets isn’t going to change what happened that day.’