(NBC News) — An account with the same handle used by the primary suspect in the mass shooting at a Buffalo, New York, grocery store posted in online chats about terrorizing an elementary school, churches and other locations he believed would have high percentages of Black people.

The Discord chat logs show the cold, racist calculus that is believed to have gone into the attack, which killed 10 people and wounded three others at a Buffalo Tops Friendly Market. Discord is a chat app that allows users to create private communities around shared interests.

On Saturday, police arrested Payton S. Gendron, 18, of Conklin, New York, whom they’ve named as the primary suspect and who has been arraigned on one count of first-degree murder.

Gendron appears to have left an extensive internet footprint and integrated his web activities into the shooting. Law enforcement officials have confirmed that Gendron maintained and used accounts on Twitch, Discord and Steam.

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