"It was pre-planned and premeditated and that's why first degree murder charges were laid," London Detective Superintendent Paul Waight told reporters.
Waight said police in London, about 200 km (120 miles) southwest of Toronto, were liaising with the Royal Mounted Canadian Police on potentially filing terrorism charges.
A Canadian man has been arrested. (Reporting by Steve Scherer Editing by Alistair Bell)

Canada's Prime Minister Justin Trudeau gives a speech during the opening of the 10th ministerial meeting of the Lima Group in Ottawa, Canada, 04 February 2019. The Lima Group holds an emergency meeting aimed at increasing pressure on Venezuela's President Maduro to leave power and consolidate support for self-proclaimed interim president Guaido, and to discuss on measures to provide economic aid as well as the humanitarian and refugee crisis. EPA-EFE/Andre Pichette