York Regional Police (YRP) say a school in Markham was placed under lockdown Tuesday morning after officers responded to what investigators have determined was a swatting call — a false emergency report intended to trigger a heavy police response.The call, which police say originated in Los Angeles, came in around 7:44 a.m. and reported that an incident was unfolding at a school near Bur Oak Avenue and Kennedy Road. Officers rushed to the scene, cleared the building and confirmed there was no threat to public safety.Swatting is a form of harassment in which someone makes a fabricated emergency call — often reporting a violent crime or imminent danger — to provoke an urgent police response.YRP say officers completed an initial sweep of the school and are now conducting a secondary clearance to ensure the building is fully secure. A police presence will remain at the school while the preliminary investigation continues.The school board enacted a lockdown as officers arrived. Due to cold weather, officials activated an evacuation protocol, relocating students to 78 Beckett Avenue in Markham, near Kennedy Road.YRP are working with the school board and says updates will follow as the investigation progresses. No injuries were reported.