The Canadian man accused of killing 10 people when he drove a rental van onto a busy Toronto street praised an "Incel Rebellion" in his apparent final social media post just prior to the massacre. So what does incel mean?
Alek Minassian, 25, has been charged with 10 counts of murder over Monday's incident, in which police say most of the victims were women.
Here are a few facts about incels and what they stand for:
- What does 'Incel' mean? -
A Canadian woman reportedly coined the term "involuntary celibates" when she launched a website more than 20 years ago to offer support to people struggling to find partners.
But since then, the 40-something woman, who asked to be identified only as Alana, said she had been saddened to see the phrase -- shortened to "incel" -- coopted by online trolls and misogynists.
It now generally refers to men who feel unable to enter into sexual relationships -- and they generally blame women.
"It was meant to be a helpful, supportive movement," she told The Globe and Mail newspaper, explaining the term was meant to include "people of all genders who find themselves celibate or lonely and not dating."
"It was a shock to discover that there was someone whose particular reason for violence was that they were lonely and celibate," she added.
- Online forums -
Incels have taken to internet message boards and forums to vent their frustrations and anger. Sexist, racist and homophobic comments are apparently common. Anti-feminist screeds are also frequent.
Lead investigator Detective Sergeant Graham Gibson on Tuesday revealed Minassian's 11th-hour Facebook post, which referred to 4chan, an online bulletin board where people post anonymously.
"The Incel Rebellion has already begun! We will overthrow all the Chads and Stacys!" Minassian's post read.
Incels refer to attractive sexually active men as "Chads" and attractive women as "Stacys."
Sites devoted to incel have been criticized for hosting violent content, and increasingly are earning police attention.
In November, online forum Reddit banned a controversial subgroup dedicated to incels -- which counted tens of thousands of members.
- US killer a role model? -
In the Facebook post, Minassian praised "Supreme Gentleman" mass killer Elliot Rodger -- a 22-year-old American who murdered six people and then killed himself in California in 2014.
Rodger -- something of a hero among incels -- had professed frustration over his virginity and women rejecting him.
In a disturbing video posted on YouTube, Rodger ranted about women who rejected and ignored him, vowing to "punish you all for it."
"I will slaughter every single spoiled, stuck-up blonde slut I see inside there. All those girls that I've desired so much, they have all rejected me and looked down upon me as an inferior man," he said.
Facebook said it had quickly identified Minassian's last post as hateful, and deleted his account.