British Columbia has sued OpenAI in California, saying a mass shooting at a school in the province could have been prevented if the company had warned local ⁠law enforcement that the shooter ⁠had used ChatGPT to ​plan the massacre.

The lawsuit filed in San Francisco federal court on Monday names OpenAI and its CEO, Sam Altman, as defendants. It is seeking damages to fund recovery efforts in the province after the February attack, as well as an order directing changes to the way the company handles ChatGPT conversations that could lead to violence.

Nine people, primarily children, were killed in the school shooting in Tumbler Ridge, British Columbia. The shooter, Jesse Van ⁠Rootselaar, had been flagged by the company’s safety team after her conversations about gun violence, but the company did not alert police.

Altman published a letter ​to the community saying he was “deeply sorry” OpenAI had not contacted ‌law enforcement. He promised reforms, but never ‌followed through, despite efforts from British Columbia’s attorney general to engage, the lawsuit says.

The school where the shooting took place is in the process of being ‌demolished, and the province has been forced to absorb the costs of a replacement school, mental health care and other effects of the shooting, according to the lawsuit.

A spokesperson for OpenAI, Drew Pusateri, called the Tumbler Ridge shooting an unspeakable tragedy. “OpenAI remains committed to working collaboratively with government and law enforcement officials, and continuing to advance our ongoing safety work.”

British Columbia’s lawsuit comes after more than 30 family members of victims and others affected by the attack filed lawsuits in California, accusing the company of opting out of a chance to prevent ‌the shooting.

Van Rootselaar shot her mother and stepbrother at home before killing an educational assistant and five students aged 12 and 13 at her former school on 10 February, according to police. Van Rootselaar, who was 18, then died by ​suicide.

Van Rootselaar’s interactions with ChatGPT were first flagged by the company in June 2025. Safety team members recommended contacting police, but Altman and other OpenAI leadership overruled them, the lawsuit says, citing OpenAI whistleblowers who spoke to the Wall Street Journal in the wake of the shooting.

The shooter’s account was deactivated, but she was able to get a new account and continue using the platform to plan her attack.

After publication of the Wall Street Journal article, the company said the ⁠account was flagged by systems that identify “misuses of our models in furtherance of violent activities”, but the issues did ​not meet its internal criteria for reporting to law ​enforcement.

The lawsuit comes after a series of ​cases against OpenAI have been filed in US state and federal courts in recent months over claims ChatGPT facilitated violence, ​including lawsuits related to a mass ‌shooting at Florida State ​University last year.

In June, Florida became the ​first state to sue OpenAI over safety risks, accusing the company of misrepresenting the safety of its ChatGPT platform, which the lawsuit said had harmed children by providing information to school shooters, offering guidance on self-harm and addicting young users.

OpenAI, which has denied the claims, has said it trains its models to refuse requests that could “meaningfully enable violence”, and notifies law enforcement when conversations suggest “an imminent and credible risk of harm to others”.