Teenager Calmly Arrested After Brutally Murdering Mother
An 18-year-old in North Wales was arrested for the hammer murder of his mother after days of captivity, a case now featured on a Channel 4 documentary.
Tristan Roberts, 18, exhibited a striking lack of emotion when police arrested him outside his home following the discovery of his mother's body. Angela Shellis, 45, was found dead in the undergrowth of Morfa Nature Park in Prestatyn, North Wales. Roberts has since been sentenced to a minimum of 22 and a half years in prison.
Roberts beat his teaching assistant mother to death with a hammer in a planned attack in October 2025. He had held Ms. Shellis captive in her bedroom for four hours, recording the ordeal, before luring her into a secluded wooded area under the pretense of allowing her to seek help. He then delivered the fatal blows and abandoned her body.
The arrest was captured on video and is being featured in the Channel 4 documentary '999: What Happened Next.' In the footage, Roberts appears calm as officers instruct him to turn around and place his hands behind his back. When asked if he was detained or arrested, he inquired about his status, a response that Detective Constable Claire Owen noted was unusual for someone his age arrested for murder.
'He came out of the house calmly. He allowed himself to be handcuffed,' DC Owen stated in the documentary. 'Potentially we thought he may have been in shock or very young and didn't understand what was going on.' Roberts also asked officers, 'Is the body that's been found my mum?' His reaction was deemed “very at odds with what you would expect.”
An investigation began when a dog walker reported finding a woman's body and a trail of blood in the park at 8:30 a.m. Police discovered a crutch, a balaclava, and gloves at the scene. Later that day, a relative raised concerns about Ms. Shellis and Roberts, who had barricaded himself inside their home.
CCTV footage later showed Roberts and his mother leaving their home at 3:20 a.m., with Ms. Shellis using the crutch. Investigators obtained further footage of the pair heading towards the Morfa site, and Roberts later returning home alone. He then left again, carrying a bag believed to contain cleaning supplies.
In the months leading up to the murder, Roberts, who had been diagnosed with autism and ADHD, expressed hateful sentiments online, particularly towards women. He allegedly used an AI tool that advised him on the best murder weapon for an inexperienced individual and provided guidance on post-killing cleanup. He also posed as his mother in texts to his brother on the day of the murder, feigning well-being.
Following the murder, Roberts posted online about the event, describing beating his mother and smashing her skull with a sledgehammer. Family members described Ms. Shellis as a devoted mother who tirelessly sought support for her son. Her sister, Sarah Gunther, told the court that Ms. Shellis would be remembered as 'a mum who never gave up,' and that the family had 'fought so hard' to get Roberts the help he needed.