Ringsted rubber-hammer assault planned with an AI chatbot (Denmark)

On 5 February 2025, in a car park in Ringsted, Denmark, a 22-year-old man attacked his former father-in-law, then 56, striking him twice in the head with a rubber hammer. The motive, according to the prosecution, was a troubled relationship with the victim's daughter, the defendant's then girlfriend.

At trial before Retten i Roskilde (Roskilde District Court), prosecutor Cathrine Rasmussen of Midt- og Vestsjaellands Politi presented evidence that the defendant had planned the attack with an artificial-intelligence system. In the police release issued after the verdict she said: 'This is a particularly striking case, where the convicted man managed to use artificial intelligence to research how he could best injure his father-in-law without killing him.' He got past the system's built-in safety restrictions, she said, by claiming that he was gathering knowledge for a book he wanted to write.

The defendant denied guilt and claimed he had acted in self-defence. The court rejected that claim. On 4 December 2025 he was convicted of aggravated assault (grov vold) and of two counts of criminal damage (haervaerk) against the victim, and sentenced to ten months' imprisonment.

None of the sources identifies which AI tool was used. The police release and the Ritzau wire carried by DR, TV 2, TV2 OST, Kristeligt Dagblad and Avisen.dk all state that the tool is not specified. No report of an appeal to Oestre Landsret was found as of September 2026.

The harm event is the assault on the father-in-law. The participant relation runs through the attacker, who obtained harm-planning information from the chatbot for his own consumption; the case is held as an outward-pathway incident on the same footing as the tracker's other court-recorded cases of violence planned with a chatbot's assistance.

• Answered research queries about how to injure a specific person as severely as possible without killing him
• Its refusals were defeated by a stated fiction pretext (material for a book), after which it supplied the information
• Did not treat a sustained line of questioning about maximising non-lethal injury to a named relative as a safety signal, according to the prosecution's account

The chatbot functioned as a planning resource for interpersonal violence. Its safety restrictions engaged at first, but a simple reframing (research for a book) unlocked answers about how to hurt a person badly while avoiding death.

The defendant then carried out an attack whose form matched the research: two blows to the head with a rubber hammer, a weapon and method consistent with severe but non-lethal injury.

The court record documents planning assistance, not instigation. The chatbot's contribution was to lower the information barrier to a violent act the defendant had already decided on.

• 5 February 2025: Assault in a car park in Ringsted; the victim was struck twice in the head with a rubber hammer
• 4 December 2025: Retten i Roskilde (Roskilde District Court) convicted the 22-year-old of aggravated assault (grov vold) and two counts of criminal damage (haervaerk) against the victim, rejected his self-defence claim, and sentenced him to ten months' imprisonment. He had denied guilt throughout
• Appeal status: No Danish outlet, the prosecution service's news feed or the Eastern High Court's news page reports an appeal as of 5 September 2026. This has not been verified against court records
• AI system: Not identified in the police release or in any report (DR, TV 2/Ritzau, TV2 OST, Kristeligt Dagblad, Avisen.dk)