It was characterized as the actions of a lone wolf — the van attack in Toronto last spring. But was it really? Alek Minassian is accused of committing one of the largest mass killings in Canadian history. Before the attack, a post appeared on Minassian's Facebook account that said "the Incel Rebellion has already begun." The term "incel" is an abbreviation for the term “involuntary celibates.” Our story looks at what is fuelling this online subculture that has proliferated in recent years. Warning: This program contains disturbing language and subject matter. Viewer discretion is advised.