Two grandparents and their infant grandchild were among four people killed in a fiery crash east of Toronto on Monday, after police pursued a robbery suspect driving the wrong way on Highway 401, Ontario’s police watchdog says.

Monica Hudon, spokesperson for the Special Investigations Unit (SIU), said the robbery suspect was also killed in the collision, which involved at least six vehicles.

All four people were pronounced dead at the scene on Highway 401 in Whitby, about 50 kilometres east of Toronto, Hudon said. Another person was taken to hospital with significant injuries, she added.