Canadian police say 10 people were killed and 15 others injured after a driver rammed a rented van into pedestrians in Toronto in what police and witnesses said appeared to be a "deliberate" attack.
But authorities initially ruled out terrorism as a motive in the attack at a busy intersection in Canada's capital late on April 23.
Public Safety Minister Ralph Goodale said on Twitter that "there appears to be NO national security connection to the horrible event." The government did not raise its terrorism alert level after the incident.
Police took the driver, who they identified as Alek Minassian, 25, into custody at the scene. They said Minassian was from Toronto and not previously known to police.
The Canadian Broadcasting Corporation aired a video it said was shot by a bystander that showed police arresting a suspect after he shouted "Kill me" and pointed an unidentified object at an officer.
Witness Phil Zullo told Canadian Press that he saw people "strewn all over the road" after the incident. "It was awful. Brutal," he said.
About 30 kilometers from the incident, foreign ministers from the Group of Seven leading industrialized countries -- the United States, Britain, Canada, France, Germany, Italy, and Japan -- were holding talks.
But Canadian authorities said their initial investigation found no connection between the events.
Former classmates at a surburban Toronto high school where Minassian was in a program for students with special needs said he would often walk the halls with his head down and hands tightly clasped, Reuters reported.