Many hours later, and long after he and other suspects had been arrested, others were still uploading the video to YouTube and other online video platforms. A Washington Post search of keywords related to the event, such as "New Zealand," surfaced a long list of videos, many of which were lengthy and uncensored views of the massacre.
And though Facebook, Instagram and Twitter have all removed Tarrant's accounts, dozens of archived versions remain available, along with the links and videos he shared.
Facebook says that it is using audio technology to detect more versions of the video, allowing it to catch more footage even if there isn't an exact match to the full version streamed by Tarrant.
On Sunday, the New Zealand government informed online platforms that sharing any version of the footage, even the edited, non-graphic versions, is a violation of the law. Facebook says that since the attack, teams have been also working to remove content in support of the massacre and other hateful posts.
The restrictions have also applied to news media. Local media reported that Sky News Australia was pulled off New Zealand broadcaster Sky TV for airing "distressing footage."
Ardern acknowledged that the problem of hate speech and the difficulty of controlling the proliferation of violent videos was a global problem.
"But it doesn't mean we can't play an active role in seeing it resolved," she added.