Toronto police say the driver who allegedly ran down and killed 10 pedestrians on a downtown sidewalk with his van left a "cryptic" Facebook message just moments before the attack.
A court Tuesday charged Alek Minassian with 10 counts of first degree murder and 13 counts of attempted murder. He kept his head down and did not enter a plea.
Police are examining what they describe as Minassian's cryptic message, hoping it will help them figure out his motive.
He praised the young man who killed six people before killing himself at a California community college in 2014 as "the Supreme Gentleman."
Police say Minassian also declared on his now-deleted Facebook account that "The Incel Rebellion has already begun. We will overthrow all the Chads and Stacys."
"Incel" is apparently social media slang for people who have no success romantically while "Chad and Stacy" refer to attractive men and women who are far more successful in finding love.
Meanwhile, Toronto police are hailing officer Ken Lam who arrested Minassian without firing a shot. Video shows Lam confronting the suspect moments after the van stopped on the sidewalk.
Minassian pointed a black object at Lam who demanded he drop to the ground. Minassian refused, challenging Lam to shoot him in the head and kill him and saying he had a gun in his pocket.
Minassian continued to approach, Lam could see he was not pointing a weapon. Lam placed his own gun in his holster as the suspect dropped to the ground and was handcuffed without a struggle.
Police say thanks to officer Lam's courage and smart action, the suspect is alive and available to answer questions.
Witnesses say Minassian drove as fast as 80 kilometers per hour for more than a kilometer down the busy sidewalk in northern Toronto, appearing to deliberately target people.
While a motive is still unclear, Canadian Prime Minister Justin Trudeau dismissed the possibility of terrorism.
"At this time we have no reason to suspect that there is any national security element to this attack," he said Tuesday. Trudeau also expressed condolences to the victims and their families.
South Korea's Yonhap news agency says two South Koreans are among the 10 dead.
Little is known about the 25-year-old Minassian at this time other than he is from the Toronto suburb of Richmond Hill was described on a social media profile as a college student.
He also briefly served in the Canadian armed forces late last year. But a defense ministry spokeswoman said Minassian asked to be discharged after just 16 days of training.