"The Elliot Rodgers and other mass killers do sometimes take on a mythical quality because, for some incels, they embody the ultimate form of resistance against a feminist culture that doesn't value them for who they are," Haenfler said.



Incels may be a recent term, Haenfler said, but in many ways the social climate that produced them has been 50 years in the making.



"What we've seen is a long-term cycle of social change in which women, people of colour, LGBTQ people, immigrants and others have demanded recognition and rights," he said. "There's the sense on the part of the incels that those rights are coming at the expense of white, heterosexual men."



Haenfler has been studying trends in alt-right and incel violence, and said he worries that things will only get worse.



"I wish, with all my heart, I could say that we've seen the last of these mass killings, but in all honesty, the cultural ingredients are there. The foundation is there. That hasn't gone away. So, in the foreseeable future, I'm very sad to say, I anticipate more of these kinds of killings."