Teenager Allegedly Inspired by ‘Dexter’ Series Accused of Fatally Attacking Mother

A teenage boy, engulfed in a toxic obsession with the notorious messaging app Discord, committed a chilling act of violence by holding his mother hostage before executing a brutal murder in the woods. Tristan Thomas Roberts, an 18-year-old with a profound disdain for women, confessed to the heinous crime, which involved luring his mother, Angela Shellis, into a deadly trap. Roberts meticulously documented the harrowing ordeal, capturing the moments he imprisoned his 45-year-old mother in her bedroom.

The sinister plan escalated when he manipulated her into venturing outdoors, where he fatally struck her with a hammer. Angela Shellis, a dedicated teaching assistant, was later found with grievous head injuries along a trail near a nature reserve in Prestatyn, North Wales. The tragic discovery was made by passersby in October of the previous year.

As Roberts faces sentencing at Mold Crown Court, he has already pleaded guilty to the murder charge. The court proceedings revealed that Roberts had obsessively researched the act for weeks, culminating in the recording of his mother’s final hours. During the trial, prosecutor Andrew Thomas KC provided chilling details, stating, “These events were recorded by Tristan Roberts on his digital audio device,” underscoring the premeditated nature of this horrific crime.

The court heard he had spent weeks researching the killing – and then digitally recorded the the last hours of his mother’s life. Andrew Thomas KC, prosecuting, said: ‘These events were recorded by Tristan Roberts on his digital audio device. ‘He made a continuous recording, lasting more than four-and-a-half hours, covering everything from the initial assault to the fatal blows at the end.’ On the recording he said: ‘This is the moment we are doing it.

We are going to hit her with a sledge hammer.’ The court heard he hit her with the hammer before strangling her. Ms Shellis was conscious before speaking in a ‘calm and firm voice’ to phone 999 for medical help.

The court heard Roberts’ violent attack began at around 11pm and lasted until 3.30am. He recorded it on a voice recorder ‘too distressing’ to be heard in court. Roberts – who was fascinated by TV serial killers – used AI search engines to research how to commit murder.

Immediately after turning 18 last October, he took advantage of being legally able to purchase knives to assemble an arsenal of weapons online and from homeware store The Range. On the night of October 23 he recorded himself holding Angela Shellis prisoner in her own bedroom before leading her to a nature reserve and killing her with a hammer he had bought on Amazon. The court heard how he spent hours on controversial gamer messaging app Discord.

The platform has been accused in the US of harbouring radical communities including white supremacist far right groups. Conservative activist Charlie Kirk’s suspected assassin, Tyler Robinson, is also reported to have been active on the site. Roberts posted disturbing content that related to murder, violence, misogyny, weapons, and his intention to kill his mother.

He used multiple aliases on chat forums. His profiles had been flagged over his abusive and threatening content, including talking openly about killing his mother, described by relatives as having ‘a heart full of love and kindness’. Roberts also had a fascination with serial killers, including TV series Dexter and movie American Psycho.

In the weeks running up to the murder he used AI search tool Deepseek to ask for tips for a ‘non-experienced killer’, including whether he should use a knife or a hammer. After it refused to engage, Roberts tricked it by lying that he was writing a book about serial killers. Although he has never explained the killing of his doting mother, and answered ‘no comment’ throughout his police interviews, in messages before the murder he said he was motivated by ‘hatred of women’.

Ms Shellis, a qualified teacher, had taken a teaching assistant post so she could spend more time at home with her two sons. But in another message, Roberts wrote that he felt ‘abandoned, betrayed and bullied’ and blamed his mother.

He said that he was killing her for ‘revenge, justice, vengeance’ and so that he could move forward in his life.

In one chilling post about his mother he wrote how he had ‘nearly traumatised myself’ by going into her bedroom while she slept with a hammer in his hand. The teenager bought weapons including knives, axes and hammers after turning 18 less than two weeks before killing his 45-year-old mother last October in Prestatyn, North Wales. Relatives knew that Roberts regularly carried a knife in his backpack, and his mother had become increasingly concerned by his behaviour.

On October 17 – four days after he had turned 18 – she messaged a social worker and friends, stating that he had bought a knife and a hammer, Mold Crown Court heard today. She had sought support for her son on numerous occasions and was again expressing concern as to his mental health.

In one note on her phone she asked: ‘Why?? What does he need these for? ‘Is he planning to hurt me, himself, what? Who? Why? FFS’. Her older son was also concerned, and before going back to university he had set up wireless-enabled cameras inside the family home so they could monitor Roberts.

In the early hours of October 18, Roberts posted messages on Discord stating that he had been standing over his mother holding a hammer when she was asleep but did not use it. The next morning, she wrote a note on her phone reading: ‘OMG… I did not sleep well at all… and Tristan kept coming into my room too – why?’ Another note read: ‘Am I safe in my room tonight?’

Her son put his murderous plan into practice after his older brother had gone back to university for the new term. Chillingly, on the night of the murder he taped himself saying: ‘This is Tristan Roberts. ‘Tonight I’m going to be Alex and I’m going to murder my mother with a sledgehammer.’ A four-hour recording started around 11pm.

It detailed an initial attack on the mother in her bedroom in which he attacked her to the head with a hammer and strangled her. Shockingly, she was kept prisoner in her room for about four hours as her son brandished the weapon. The recording – deemed far too harrowing to be played in court today – captures Ms Shellis pleading for him to call 999 and get help.

She remained calm, even saying she would ‘back him up and say that he had not known what he was doing’, prosecutor Andrew Thomas KC said. He then cynically convinced her to leave the house under the pretence that she could have her injuries treated. Instead he tricked her into taking a ‘short cut’ through a nature reserve where he took the sledgehammer out of his rucksack and began repeatedly attacking his screaming mother.

Roberts – whose previously long straight hair had been cut to a short crop before today’s hearing – cast his gaze downwards from his seat in the glass-panelled dock as the ‘catastrophic’ injuries he inflicted were spelt out.