Has to be a single event (so no completely unrelated murders). There has to be solid evidence, e. g. chat logs, a manifesto, explicit statements by the killer, that the killer was motivated in part by some ideology and not just insanity.

After such an event occurs, I will wait at least one month after the deaths to resolve, since the aftermath of such attacks often involve a lot of smoke/uncertainty. Additionally, immediate speculation after the deaths seems disrespectful.