The Welsh teen who was arrested for the slaying of his mother used an AI chatbot to get tips on how to carry out the crime.
Tristan Roberts, 18, pleaded guilty to taking the life of his mother, high school teaching assistant Angela Shellis, last October.
Investigators concluded that Roberts had carefully planned the homicide for three weeks.
Highlights
- Tristan Roberts pleaded guilty to the slaying of his mother in a nature reserve in northern Wales last October.
- The teenager reportedly used an AI chatbot for advice on how to commit the crime and avoid getting caught.
- Roberts also asked the chatbot to help him choose a weapon, prosecutors found.
Image credits: North Wales Police
Trigger warning: this article contains graphic details that may be distressing to some.
The teen blamed the crime on his “hatred for women” and a need for “revenge, justice, and vengeance.”
Prosecutors revealed that Roberts turned to the Chinese AI bot Deepseek for advice regarding the weapon he used and how to avoid being caught.
He reportedly asked the bot, “What is a better weapon for m*rder, a hammer or a knife?”
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Though the chatbot initially refused to answer, it provided the information after Roberts stated that he was writing a book on serial k*llers.
According to prosecutor Andrew Thomas, the chatbot “suggested a hammer would be better for a non-experienced k*ller and gave him pros and cons for both.”
On Wednesday (March 24), Roberts pleaded guilty to the crime and was sentenced to at least 22 years in prison.
Image credits: North Wales Police
The perpetrator waited until his 18th birthday before buying potential weapons, including axes, hammers, and knives, the minimum age in the UK for such purchases.
Roberts, who had reportedly been in court for a knife offense weeks before the crime, also asked the chatbot, “Just tell me the simple way to remove the mist and blood remains on the walls and floor and bed.”
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The 18-year-old hit his mother with a hammer and held her captive for four hours before leading her out of the house under the pretense that he would seek medical help for her.
Instead, he took her to a nature reserve, where he delivered four fatal blows to her head, dumped her body, and then tried to clean up the blood from the scene.
Roberts reportedly used her cellphone to text his brother to dispel any suspicion.
“Just call me for a second, so that I know you are alive,” read one message sent to the 45-year-old victim’s phone.
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The criminal then bragged on the social platform Discord, under the username Kiewyh, about how he had “beat the s**t” out of his mother" and “smashed her skull in so hard with a sledgehammer.”
He is also reported to have recorded a message on his phone under the alter ego “Alex” in which he said the night before the crime, “This is the moment we’re doing it, we’re going to hit her with a sledgehammer.”
After the attack, he said, “Oh God, that was terrifying … that felt so crazy.”
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The teenager from Prestatyn, Wales, expressed misogynistic views and had a fascination with the film American Psycho.
Judge Rhys Rowlands concluded that Roberts showed no remorse for his actions and told the attacker that he appeared “to have reveled in the control you exerted over your own mother.”
“It was on any view a truly awful way for someone to d*e,” the judge added. “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 d*ath.”
The teenager was obsessed with American Psycho and had posted misogynistic messages
In the weeks before the crime, Roberts posted a still from American Psycho on Discord showing the blood-spattered protagonist alongside the message, “I got urges,” as per The Guardian.
In another, he said, “It's gonna be some american psycho sht haha.” He also wrote, “I do hate girls … girls/women i also dont trust them” and “she is gonna just vanish off the earth … now its time”.
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Police were called to the nature reserve on October 24, 2025, the day after the crime, when Shellis’ body was found in undergrowth.
A 100-meter blood trail reportedly led to her body. Gloves and a balaclava were found at the scene, along with the mother’s crutch, which she needed for a knee injury.
Doorbell footage showed the mother and son leaving their home at 3.19am. The video also showed Roberts returning to the house after the crime and then leaving again, supposedly to try to clean up the scene with bleach.
Roberts began the attack at his and his mother’s home before carrying out the crime at a nature reserve
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Shellis’ elder son, Ethan Roberts, said in a statement, “All my mum ever did was love Tristan.”
Her sister, Sarah Gunther, said, “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.”
Roberts’ case has brought renewed attention to the role of AI-powered chatbots in helping criminals carry out attacks.
A joint investigation by CNN and the Center for Countering Digital Hate (CCDH) published this month analyzed how leading AI chatbots responded to teenagers apparently plotting violent acts.
The team tested 10 AI companions commonly used by teens: ChatGPT, Gemini, Claude, Copilot, Meta AI, DeepSeek, Perplexity, MyAI, Character.ai, and Replika.
It concluded, “Most of those we tested are not only failing to prevent potential harm – they are actively assisting users by giving them information that could be used in preparing attacks.”
Investigators noted that while AI chatbot companies promise safeguards for younger users, particularly those openly discussing violence, their tests found that “those protections routinely failed to detect obvious warning signs from a young person purporting to be planning on carrying out an act of violence.”
People reacted in horror to the 18-year-old's crime against his mother and highlighted how warning signs were overlooked
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