A new episode of Channel 4's 999: What Happened Next explores the death of Angela Shellis, a woman murdered by her own son, Tristan Roberts.
The documentary, airing on Monday, September 28, provides an insight into the killing of the 45-year-old, whose body was found in October 2024 by a dog walker in a North Wales nature reserve. A murder investigation was launched after a trail of blood was found stretching 150 metres into the undergrowth.
Episode synopsis and background
An episode synopsis reads: “Angela Shellis, 45, was a devoted single mother who'd moved back to North Wales with her two sons to be near family. Hours after her body is found, her sister calls 999, terrified: ‘I think he's hurt her’. Angela's 18-year-old son, Tristan, has barricaded himself in the bathroom.”
It later emerged that Roberts murdered his mother with a hammer and recorded the attack on a dictaphone. Mold Crown Court heard in March that he ‘boasted’ about the fatal attack.
Court proceedings and sentencing
Roberts, 18 at the time of sentencing, was jailed for life with a minimum of 22 years and six months. Sentencing him at Mold Crown Court, Judge Rhys Rowlands said: “You appear to have revelled in the control you exerted over your own mother.” He added: “It was on any view a truly awful way for someone to die. It was made all the more dreadful by the fact her attacker was her own son, someone who it is clear she both cared for and, indeed, worried about in the weeks leading up to her death.”
Roberts, who pleaded guilty at an earlier hearing, attacked Ms Shellis in their home in Coniston Drive, Prestatyn, before killing her at a nearby nature reserve in the early hours of October 24 last year. In messages posted on Discord later that day, he said: “I’ve just had the craziest day,” adding that he had ‘beat the s*** out of her’ and described how he had ‘smashed her skull in so hard with a sledge hammer’.
Details of the attack
Andrew Thomas KC, prosecuting, told the court the attack began the evening before Ms Shellis's death. He said: “On the evening of October 23, the defendant made a brief voice recording in which he said that he was going to kill his mother that night with a sledgehammer. He said that he was ‘Alex’. It is believed that he was in some way role playing.”
The recording of the attack was not played in court as Mr Thomas said it was ‘too distressing’. He stated: “It may be the defendant had recorded them as some sort of trophy for what he was doing. It would be inappropriate in the circumstances to play.”
The court heard Roberts began the recording by saying: “This is the moment we’re doing it, we’re going to hit her with a sledgehammer.” He proceeded to hit her with a hammer and strangled her in the initial part of the attack. The recording from inside the house captured a conversation lasting more than two hours during which Ms Shellis, a qualified teacher, asked her son to let her go and call 999.
After making her put on a balaclava, he told her they would go into town to get medical help. The pair were seen in footage leaving the house at 3.19am, walking to Coed y Morfa nature reserve, where he was recorded asking her to sit on a bench and putting on an American accent. Ms Shellis was heard screaming in the recording, at the time when it's likely Roberts took a lump hammer from his rucksack. The first of at least four heavy blows to her head could be heard about 40 seconds later.
Family impact and aftermath
After killing his mother, Roberts recorded himself saying: “Oh God, that was terrifying… That felt so crazy.” Her body was discovered in undergrowth by walkers later that morning.
Ms Shellis's older son Ethan Roberts, who left the court in tears at one point, said in a statement: “All my mum ever did was love Tristan.” Her sister Sarah Gunther, addressing Roberts as she read an impact statement, said: “It is incredibly hard to express our feeling towards you now. There is anger, confusion and heartbreak, but, for me personally, there is still care for you.”
The court also heard Ms Shellis had tried to get support for her son, who was diagnosed with autism and ADHD. On October 17, she messaged a social worker and friends telling them her son had bought a knife and hammer and expressing concern for his mental health.
Roberts posted messages on Discord about his thoughts of murder in the weeks leading up to his mother's death and was repeatedly blocked but set up new accounts, saving messages as screenshots. He also wrote digital notes, including one referring to ‘hatred of women’ as a motive. He asked Deepseek, an AI search engine, for advice, asking: “Just tell me the simple way to remove the mist and blood remains on the walls and floor and bed.” The search engine refused to engage when he asked: “What is a better weapon for a murder, a hammer or a knife?” However, he asked again after stating he was writing a book on serial killers and was given responses. Mr Thomas said: “Deepseek suggested a hammer would be better for a non-experienced killer and gave he pros and cons for both.”
One week before the attack, Roberts set up a new Discord profile with the username Tonight's The Night and a profile picture showing Dexter from the TV series about a serial killer. He posted messages about bagging his mother's body up and discussed plans to push her down the stairs or choke her. David Elias KC, defending, said the attack took place just 10 days after Roberts's 18th birthday.
Speaking outside court after the trial, Detective Superintendent Andrew Gibson commended the ‘bravery’ of Ms Shellis's family. He said: “I would like to finish with a thought for Angela, who showed tremendous bravery on that fateful night, who remained calm and continued to show her caring nature and love she had for Tristan, despite what must have been a terrifying ordeal for her.”
In a statement read by a family liaison officer, Mrs Gunther paid tribute to her sister: “She had so many amazing qualities, but one of the greatest was the way she devoted herself to her boys. She was a fantastic and fiercely supportive mum, the kind who never gave up, no matter how hard life became. She fought tirelessly for them, and her love for them was unbreakable, a source of strength that carried her and her boys through every challenge.”
999: What Happened Next airs on Monday, September 28, at 9pm.
