The shooter, Payton Gendron, acted out of racist beliefs. Eleven of his victims were black. Gendron used the chat room on the Discord platform for months as a kind of diary. He wrote his thoughts on it and posted pictures of himself with guns. It was not known that he gave others access to the space.
The New York Times relies on a Discord spokesperson, who said that Gendron invited a select group of people about thirty minutes before the attack. According to the spokesperson, all invitees accepted the invitation. Who they were is unknown. Gendron also planned to livestream his act to the platform. Whether he actually did so is still under investigation.