A Facebook message posted before the Toronto van attack in which 10 people died suggests the suspect hated women and people with active sex lives.
It also evoked memories of previous attacks, including a 1989 massacre of 14 women by a man who blamed feminists for his problems.
The gender issue arose because of what police called a "cryptic" Facebook message posted by Toronto suspect Alek Minassian just before Monday's carnage.
It suggested he was part of an online community angry over their inability to form relationships with women.
The now-deleted post saluted Elliot Rodger, a college student who killed six people and wounded 13 in shooting and stabbing attacks near the University of California, Santa Barbara, in 2014.
Calling Rodger "the Supreme Gentleman", the Facebook post declared: "The Incel Rebellion has already begun! We will overthrow all the Chads and Stacys!"
Chads and Stacys are names used in internet forums to denote people with more active sexual lives.
A crowd gathered in Toronto's North York community to pay their respects to the victims at a memorial of roses, candles and messages of condolence.
"I needed to come here to show that I'm not afraid of this city," said Meena Chowdry, wiping away tears.
"That one man's actions cannot taint an otherwise beautiful, welcoming city."
Minassian (25) was charged with first-degree murder over the deaths of 10 pedestrians mowed down by a rented van. Fourteen others were injured.
Det Sgt Graham Gibson told a news conference that those killed and injured were "predominantly" women, though he declined to discuss a possible motive.
Authorities have yet to release a list of victims, but those known to have been killed include a 30-year-old woman who was active in volunteer work and a female student at Seneca College, which Minassian attended.
A Jordanian citizen and two South Koreans were also among those killed.
The reference to the term "incel", meaning involuntarily celibate, was a term used by Rodger in online posts raging at women for rejecting him romantically.
The anti-women sentiment also recalled Canada's 1989 massacre at the Ecole Polytechnique in Montreal, when 25-year-old Marc Lepine entered a classroom.
He then separated the men from the women, told the men to leave and opened fire, killing 14 women before killing himself.
In a suicide note, he blamed feminists for ruining his life.
Since then, there have been sporadic mass shootings in Canada, but none with a higher death toll.
That reinforces the view among many Canadians that their country is less violent than the United States.
Wendy Cukier, a professor in the business school at Toronto's Ryerson University and president of Canada's Coalition for Gun Control, said Canada might avoid some types of violence because its social programmes were stronger than those in many US states.
How- ever, the main difference, she contends, is tighter gun regulations in Canada.
"If you take guns out of the mix, Canada and the US are identical," she said, citing statistics indicating the two countries have similar rates of non-firearm homicides.
Although police said Monday's rampage did not appear linked to international terrorism, the use of a vehicle to kill mirrored tactics used by terrorists in France, Germany, Spain, New York and elsewhere.
Since 2014, there have been at least two terror-related cases in Canada of vehicles being used as weapons, causing several injuries and one death.
Overall, however, Canada has been spared high-casualty terror attacks.
Its most striking incidents of violence in recent years have varied in nature.
In 2014, a Can- adian Muslim shot a member of the honour guard at Ottawa's national war memorial, then stormed parliament, where he was shot dead by sergeant-at arms Kevin Vickers, now Canada's ambassador to Ireland.
Last year, a French-Canadian man fatally shot six Muslim men during evening prayers at a mosque in Quebec City.
Rapper Maestro Fresh Wes returned to the scene of the van rampage on Tuesday, pausing by a newly-erected memorial.
Wes was strolling in Yonge Street to get a haircut when he saw a body bag on the ground.
"Yesterday was the most beautiful day of the year and then look what happened," he said.
"Toronto is a safe city, but these things could happen anywhere."
Also revisiting the site was Saman Tabasinejad, a New Democrat Party politician who was canvassing in the area when the attack happened.
"I saw glass everywhere, a fire hydrant knocked over and then five body bags," she said.
"People were holding others and I saw solidarity.
"When something like this happens, you think people are going to run away from the tragedy, but people didn't - they ran towards it to try to help others."