Alek Minassian, the van driver accused of killing 10 people in Toronto posted to Facebook minutes before the attack to praise killer Elliot Rodger and refer to the misogynistic "incel" Reddit group.
Minassian, 25, was charged on Tuesday with 10 counts of murder and 13 counts of attempted murder.
Police say he appeared to intentionally strike pedestrians after mounting a busy pavement in a rental van.
He was arrested several blocks away after a tense standoff with police.
Mr Minassian's Facebook post, which the social network has confirmed as real, praised Elliott Rodger, a 22 year old from California who killed six people in a shooting rampage through Isla Vista, California in 2014 before turning the gun on himself.
It read: "The Incel Rebellion has already begun! We will overthrow all the Chads and Stacys! All hail the Supreme Gentleman Elliot Rodger!"
The term "incel" refers to a now-banned group on the message site Reddit, used by Rodger, where young men discussed their lack of sexual activity and attractiveness to women - often blaming women for the problem.
"Chads and Stacys" refers to attractive men and women who are perceived as better than or unavailable to "incels", which is short for "involuntary celibate".
Toronto Police Detective Sergeant Graham Gibson said at a press conference on Tuesday that the 10 dead and 14 wounded were "predominantly" women.
He said the youngest were in their twenties and the eldest in their eighties.
Authorities have not yet formally identified any of the victims.
Mr Minassian appeared in court on Tuesday to hear the charges against him. He sported a shaved head and white jumpsuit and held his hands behind his back, showing little emotion throughout.
He was ordered to have no contact with surviving victims and to return to court on 10 May.
A man believed to be a relative of Mr Minassian's sat in the front row of the court and wept. Asked by reporters after the hearing if he had anything to say, the man replied "sorry".
Canadian Prime Minister Justin Trudeau called the incident a "senseless attack and a horrific tragedy".
Yonge Street, where the attack took place, remained closed on Tuesday as police continued their investigation.
A line of officers standing shoulder-to-shoulder walked slowly down the street combing it for remaining evidence.
What else do we know about the suspect?
The Canadian Armed Forces (CAF) confirmed that Mr Minassian was a member for two months in late 2017. He requested to be voluntarily released.
Mr Minassian had previously attended a school for students with special needs in north Toronto, former classmates said.
He would be seen walking around Thornlea Secondary School with his head down and hands clasped tightly together making meowing noises, Shereen Chami told Reuters.
But she said Mr Minassian had not been violent. "He wasn't a social person, but from what I remember he was absolutely harmless," she told Reuters.
Mr Minassian went on to attend Seneca College in the North York area of Toronto, where the van incident took place, CBC reported.
What we know about Alek Minassian
Police say Mr Minassian is from the northern Toronto suburb of Richmond Hill and was not previously known to authorities.
Public safety minister Ralph Goodale said there "would appear to be no national security connections" and Canadian broadcaster CBC cited government officials as saying Mr Minassian was not associated with any known terror groups.
Who were the victims?
So far three victims have been named in the media and through other channels.
Anne-Marie D'Amico worked for the US investment company, Invesco, CBC reports. The company's Canadian headquarters are on Yonge Street.
The Jordanian embassy in Ottawa has told the BBC that one of its citizens was among the victims. Jordanian media named him as Munir Abdo Habib al-Najjar, who they said was in Canada to visit one of his sons.
Toronto resident Dorothy Sewell, 80, has also been named by relatives as one of the victims.
Her grandson, Elwood Delaney, said she was the "best grandma anyone could have asked for".
The South Korean embassy in Canada confirmed to the BBC that two of its citizens were among the dead and another was critically ill. Their names have not been disclosed.
The 15 injured remain in hospitals throughout Toronto.
How did the incident unfold?
Police said the suspect in the van mounted the kerb on Yonge Street between Finch Avenue and Sheppard Avenue at about 13:30 local time (17:30 GMT) on Monday and drove into pedestrians along a 1km (0.6-mile) stretch.
Reza Hashemi, who owns a video shop on Yonge Street, told the BBC he heard screaming on the other side of the road. He said the van was repeatedly mounting the pavement and running into people.
One witness told City News that the driver was "hitting anything that comes in the way".
"People, fire hydrants, there's mail boxes being run over," said the unnamed man, who said he was driving behind the van during the incident.
As the van continued, the man said he sounded his horn to try to warn pedestrians. "I witnessed at least six, seven people being hit and flying in the air, like killed, on the street," he said.
Pictures from the scene showed bodies covered in orange sheets along the van's route. Debris and items of clothing were scattered across the pavements and road.
The van was brought to a halt by police several streets away and was quickly surrounded.
The suspect pointed an object at the officer and claimed to have a gun.
"I don't care. Get down," the officer said, before arresting Mr Minassian without firing a shot. The arrest was filmed by two bystanders and the officer was praised for not opening fire.
A makeshift memorial has sprung up at the junction of Yonge Street and Finch Avenue and a wall is being filled with messages of condolences, grief and support.
One of those who came to lay a flower, Dave Spence, said residents would "walk a little differently" when they came through the area "for years to come".