Toronto: The deadly van rampage in Toronto is training attention on an online world of sexual loneliness, rage and misogyny after the suspect invoked an uprising by "involuntary celibates" and gave a shout-out to a California killer who seethed at women for rejecting him.

The world of self-described "incels," where sexual frustrations boil over into talk of violent revenge against women, has become a virtual home for some socially isolated men like the 25-year-old computer science student charged in Monday's carnage on Toronto's busiest thoroughfare.

Minutes before ploughing a rented van into a crowd of mostly women, killing 10 people and injuring 14, suspect Alek Minassian posted a Facebook message that seemed to offer one of the few clues so far to what was on his mind. "The Incel Rebellion has already begun!" it read.

Police confirmed Minassian posted the message but have declined so far to discuss a motive for the attack as they continue investigating. But the post has revived concerns about the anti-woman vitriol embraced by California mass killer Elliot Rodger and invoked by Minassian in his post.