THE self-proclaimed racist believed to have killed 49 people at a New Zealand mosque during Friday prayers apparently opened fire with rifles covered in white-supremacist graffiti and listened to a song glorifying a Bosnian Serb war criminal.

The details highlight the toxic belief system behind an unprecedented, live-streamed massacre, which prime minister Jacinda Ardern described as “one of New Zealand’s darkest days”.

Trying to understand what motivated the slaughter may be difficult, as some of the material posted by Brenton Tarrant resembles the meme-heavy hate speech prominent in dark corners of the internet.

At least two rifles used in the shooting mention Ebba Akerlund (pictured below), an 11-year-old girl killed in an April 2017 truck-ramming attack in Stockholm by Rakhmat Akilov, a 39-year-old Uzbek man.

The number 14 is also seen on the gunman’s rifles. It may refer to 14 Words, which the Southern Poverty Law Centre says is a white supremacist slogan linked to Adolf Hitler’s Mein Kampf. He also used the symbol of the Schwarze Sonne, or black sun, which “has become synonymous with myriad far-right groups”, according to the centre, which monitors hate groups.

In photographs from a now deleted Twitter account associated with the suspect that match the weaponry seen in his live-streamed video, there is a reference to Vienna 1683, the year the Ottoman Empire suffered a defeat in the siege of the city at the Battle of Kahlenberg. Acre 1189, a reference to the Crusades, is also on the guns.

The name Charles Martel, who the Southern Poverty Law Centre says white supremacists credit “with saving Europe by defeating an invading Muslim force at the Battle of Tours in 734”, was also on the weapons.

They also bore the inscription Malta 1565, a reference to the Great Siege of Malta, when the Maltese and the Knights of Malta defeated the Turks.