Christchurch: Online accounts linked to gun attacks that killed 49 people and wounded at least 20 at two New Zealand mosques on Friday had in recent days circulated white supremacist imagery and extreme right-wing messages celebrating violence against Muslims and minorities on social media and message boards.

A gunman broadcast live footage on Facebook of the attack on one of the mosques. Police later said four people, who they did not identify, were in custody and one had been charged with murder over the country’s worst ever mass shooting.

On Wednesday, the Twitter handle @brentontarrant tweeted pictures of one of the guns later used in the mosque attacks in the city of Christchurch. It was covered in white lettering, featuring the names of others who had committed race- or religion-based killings; Cyrillic, Armenian and Georgian references to historical figures and events; and the phrase: “Here’s Your Migration Compact.”

The number “14” was written on the side of the rifle as well, a reference to the “fourteen words,” a white supremacist mantra.

Other tweets from the same user on that day included references to declining white fertility rates, articles about right-wing extremists in various countries and stories about purported crimes by illegal immigrants.

The Twitter profile had 63 tweets, 218 followers and was created last month.

A person involved with the attacks also appeared to post regularly to the “/pol/ — Politically Incorrect” forum on 8chan, a online discussion site known for allowing virtually any content, including hate speech. About 1:30pm (0030 GMT) on Friday, the anonymous user told the group “I will carry out and attack against the invaders, and will even livestream the attack via Facebook;” approving responses to the post included Nazi images and memes.

The post featured a link to a 74-page manifesto that said he was motivated by “white genocide,” a term white supremacists use to describe immigration and the growth of minority populations. It also linked to a Facebook page for a user called brenton.tarrant.9, where the attack was livestreamed.

The @brentontarrant Twitter account was suspended not long after the shooting on Friday, as was the brenton.tarrant.9 Facebook page.

Agence France-Presse