Holly Newton was stabbed to death by her ex-boyfriend Logan McPhail in January last year after she ended their relationship.
McPhail, who was 16 at the time of the attack and is now 17, was handed a life sentence for murder with a minimum term of 17 years in custody at Newcastle Crown Court on Friday following a six-week trial.
The court heard that their 18-month relationship, which began after the teenagers met at Army Cadets, showed signs of coercive control and domestic abuse which Holly’s mother Micala Trussler said her daughter was “was too young to recognise”.
On the day of her death, when McPhail inflicted 36 knife wounds on Holly, he had travelled from Gateshead to Hexham in Northumberland armed with a kitchen knife and wearing a snood to cover his face, before following Holly and her friends for around 45 minutes.
He also made repeated contact with those close to Holly through voice messages in a bid to convince her to meet up with him face-to-face.
After the trial, detective sergeant Darren Davies, of Northumbria Police, said: “This is a truly devastating case where Holly’s future has been cruelly taken away at the hands of her ex-boyfriend.
“While we may never know the full story, it is clear that MacPhail was unhappy with Holly after their relationship had recently ended.
“He was unable to move on and was adamant on speaking with her face-to-face that night. Nothing other than seeing Holly in person was going to be enough.”
Holly’s family have called for age thresholds linked to incidents of domestic violence to be lowered following the trial. Currently the abuser and the victim must be over 16 for it to be considered a domestic abuse crime.
Speaking on BBC Radio 4’s Today Programme, Yvette Cooper, said this was an "extremely important issue".
"We will specifically look at this, because we need to make sure that we have got the right ways of recording this kind of violence in teenage relationships," Cooper said.
"I do think that this is an extremely important issue and we have to take seriously the points that they have made."
McPhail, who has autism and other complex needs, had previously admitted manslaughter and possession of a bladed article but denied murder and grievous bodily harm with intent.
He was also handed a five-year prison sentence for grievous bodily harm with intent which will run concurrently for stabbing a friend of Holly’s who attempted to intervene in the attack.
