A lone white supremacist is the suspect in the Christchurch mosque killings. But under New Zealand law, many others could face charges for spreading or perhaps even possessing all or part of the 17-minute Facebook Live video streamed by the killer as he methodically shot the victims.
As of Thursday, at least two people had been charged with sharing that video via social media, under a law that forbids dissemination or possession of material depicting extreme violence and terrorism. Others could face related charges in connection with publicizing the terrorist attack, under a human-rights law that forbids incitement of racial disharmony.
https://www.nytimes.com/2019/03/21/world/asia/new-zealand-attacks-social-media.html