Livestreamed carnage: Tech's hard lessons from mass killings

These days, mass shooters like the one now held in the Buffalo, N.Y., supermarket attack don’t stop with planning out their brutal attacks. They also create marketing plans while arranging to livestream their massacres on social platforms in hopes of fomenting more violence.

Sites like Twitter, Facebook and now the game-streaming platform Twitch have learned painful lessons from dealing with the violent videos that now often accompany such shootings. But experts are calling for a broader discussion around livestreams, including whether they should exist at all, since once such videos go online, they're almost impossible to erase completely.

The self-described white supremacist gunman who police say killed 10 people, most of them Black, at a Buffalo supermarket Saturday had mounted a GoPro camera to his helmet to stream his assault live on Twitch, the video game streaming platform used by another shooter in 2019 who killed two people at a synagogue in Halle, Germany.

He had previously outlined his plan in a detailed but rambling set of online diary entries that were apparently posted publicly ahead of the attack, although it's not clear how may people might have seen them. His goal: to inspire copycats and spread his racist beliefs. After all, he was a copycat himself.

He decided against streaming on Facebook, as yet another mass shooter did when he killed 51 people at two mosques in Christchurch, New Zealand, three years ago. Unlike Twitch, Facebook requires users to sign up for an account in order to watch livestreams.

Still, not everything went according to plan. In particular, by most accounts the platforms responded more quickly to halt the spread of the Buffalo video than they did after the 2019 Christchurch shooting, said Megan Squire, a senior fellow and...