OpenAI said it considered notifying the Royal Canadian Mounted Police about a user later responsible for a mass shooting.
The company flagged the account in June for potential “furtherance of violent activities”.
At the time, investigators found no credible or imminent threat.
That meant the case did not meet the threshold for referral to law enforcement.
The suspect, Jesse Van Rootselaar, killed eight people in British Columbia before taking their own life.
After the attack, OpenAI contacted the RCMP and shared information about the account.
The company said it will continue to support the investigation.
Police said the 18-year-old first killed family members at home and then attacked a nearby school.
Victims included a teaching assistant and five students aged 12 to 13.
The motive remains unclear.
The shooting is Canada’s deadliest since the 2020 Nova Scotia killings.
The case has renewed debate about how tech companies assess threats and when they should alert authorities.
