British Columbia has sued OpenAI and its chief executive, Sam Altman, alleging that the company failed to alert police after detecting violent activity on a ChatGPT account belonging to the teenager who later carried out the Tumbler Ridge school shooting.

The lawsuit was filed in a federal court in San Francisco by the provincial government and the local school district. It accuses OpenAI of negligence, product-liability violations and aiding and abetting the February 10 attack, in which eight victims were killed and more than 25 people were injured.

Eighteen-year-old Jesse Van Rootselaar first killed her mother and stepbrother at their home before attacking Tumbler Ridge Secondary School. Five students aged 12 and 13 and an educational assistant were killed at the school. Van Rootselaar subsequently died by suicide, bringing the total number of deaths to nine.

The allegations against OpenAI centre on conversations Van Rootselaar reportedly had with ChatGPT months before the shooting. According to the complaint, the company’s automated systems detected discussions involving gun violence in June 2025 and referred the account for an internal safety review.

The lawsuit alleges that members of the safety team considered the activity serious enough to recommend contacting law enforcement. OpenAI instead deactivated the account without informing Canadian authorities. Van Rootselaar allegedly created another account and continued using the platform before the attack.

OpenAI has described the attack as an unspeakable tragedy and said it remains committed to working with governments and law-enforcement agencies. The company has previously said its systems are designed to reject requests that could meaningfully assist violence and that it contacts authorities when conversations indicate an imminent and credible threat to others.

The company has acknowledged that the account connected to Van Rootselaar was identified and banned before the shooting. However, it said the activity did not meet its internal threshold for referral to police. Altman later apologised to the Tumbler Ridge community for the company’s failure to issue a warning and promised further safety improvements.

British Columbia is seeking compensation for the costs imposed by the attack, including mental-health care, emergency assistance and the replacement of Tumbler Ridge Secondary School. The damaged school is being demolished, while the provincial and federal governments have allocated about C$200 million for rebuilding and community recovery.

The province is also asking the court to order changes to how OpenAI handles conversations suggesting a risk of violence. Attorney General Niki Sharma has argued that technology companies should not be shielded from responsibility when their products reveal information capable of preventing serious harm.

The government’s case joins 37 lawsuits filed by survivors and relatives of victims. Those proceedings similarly accuse OpenAI of failing to act on warning signs and allowing the attacker to return to ChatGPT after her original account was disabled.

The outcome could help determine how far an artificial-intelligence company’s duty extends when its systems detect violent intentions. At the centre of the dispute is whether identifying a threat creates an obligation to report it—and whether a failure to do so can make a technology provider legally responsible for part of the resulting harm.