Police and federal officials said Sunday that the man suspected of stabbing a police officer and plowing a van into pedestrians on Saturday night is a 30-year-old refugee from Somalia, who had been interviewed by the RCMP in 2015. Police and politicians urged Canadians to be vigilant, but called for calm and unity in the wake of a terrorist attack in Edmonton that injured five and led to the arrest of a 30-year-suspect who had previously been investigated for espousing extremist views. It is the second major terrorist attack in Canada this year, following January’s shooting at a mosque in...