The gunman’s efforts were clearly choreographed for internet fame and to spread a message of hate. Minutes before the attacks started, he published a manifesto to message boards where white supremacists gather, and included a link to the page where the streaming video of the shooting would appear.

But experts say it may not be enough to focus just on that content. New Zealand, like many countries, has often struggled with how seriously to take white supremacy, offline and online.

Anjum Rahman, the head of the Islamic Women’s Council of New Zealand, reported that her organization had tried to warn the government for years about growing vitriol toward Muslims and the rise of the so-called alt-right in New Zealand. In an op-ed for The Spinoff, a news website, she said her organization had asked for help from New Zealand’s security agencies and had written a “comprehensive report” for the government five years ago, outlining the group’s concerns.

“As far as we know, nothing concrete was done with that report,” she wrote.

In fact, one of the two mosques attacked Friday had pigs’ heads delivered to it in 2016 by men who gave Nazi salutes.

Jarrod Gilbert, a University of Canterbury sociologist who studies gangs in New Zealand, said that when Christchurch had a problem in the 1980s and 1990s with white supremacist skinheads, the authorities tended to dismiss them as a fringe group “because people never really wanted them here.”