During the trial, jurors heard that, shortly before Holly’s death, her mother, Micala Trussler, had been so concerned about the boy that she called the police.
The circumstances were so severe that it was agreed Holly should not leave school if the boy was outside.
Holly was “extremely nervous” about him turning up after school on the day of her death but, when there was no sign of him, she went shopping with her friends, unaware he was tailing her.
The trial heard that the boy followed her around the town centre for about 45 minutes as she shopped.
Holly had told a friend hours before she was killed that the boy was “basically stalking” her, jurors heard.
He asked to speak to her when he saw her outside a pizza shop, lured her down an alleyway and then attacked her with a knife.
He narrowly avoided killing the teenage boy who was with Holly that day and who tried to step in to save her.
Hexham is a market town on the banks of the River Tyne, close to Hadrian’s Wall. It contains several buildings of historical importance, most notably Hexham Abbey, which dates from about 1170.
Jurors were sent out to start deliberations on Tuesday, and Justice Hilliard thanked the panel for their careful consideration of the facts. He will pass sentence over two days, on October 31 and November 1.
The defendant, watching proceedings from a secure unit via video link, did not appear to react when the foreman delivered guilty verdicts for the counts of murder and wounding with intent.
In an unusual step, the judge invited Trussler to pay tribute to her daughter before the jury dispersed so that they had a better picture of the kind of girl she was.
Justice Hilliard said: “The focus has been about the defendant in this trial and you have only heard his view of Holly. Before you depart, I wanted you to have a more complete understanding of her and what she was like.”
Trussler, from Haltwhistle, Northumberland, stepped out of the public gallery and described how her “beautiful child” had loved her family, sport, animals and dancing.
“She grew into a happy teenager who would do anything for anyone. At school, Holly was a quiet student who just got on with her work. There was never a bad report from her teachers.
“When Holly started at the Queen Elizabeth High School in Hexham, she felt like she belonged. She had such a tight-knit group of friends who were always there for each other.”
Her cat Maxi miaowed every morning to be let into her room, Trussler said, adding: “To this day, Maxi still does this. However, Holly isn’t there to open the door.”
The judge said: “It is the kind of devastation that knives leave in their wake when people carry them and use them.”
