New Delhi, June 24 -- The suspect accused of killing a police officer outside a Montreal hotel had a manifesto that links him to an online community of frustrated men who talk about attacks against people who have sex, an official familiar with the matter confirmed Tuesday.

The suspect armed with a long gun opened fire Monday before officers returned fire, killing him, police said.

The official, speaking on condition of anonymity as they were not authorized to speak publicly about the case, said the manifesto links the suspect to the "involuntary celibate" or "incel" ideology, a mostly online group of people, primarily men, who believe society unjustly denies them sexual or romantic attention.

The manifesto prompted a warning to police...