The document appears to chronicle how Payton Gendron allegedly planned his attack two months before the deadly rampage at Tops Friendly Market in Buffalo, according to law enforcement sources. READ MORE: https://abcn.ws/3PrmOa0 SUBSCRIBE to GMA's YouTube page: https://bit.ly/2Zq0dU5 SIGN UP to get the daily GMA Wake-Up Newsletter: https://gma.abc/2Vzcd5j VISIT GMA's homepage: https://www.goodmorningamerica.com FOLLOW GMA: TikTok: https://tiktok.com/@gma Instagram: https://instagram.com/GoodMorningAmerica Facebook: https://facebook.com/GoodMorningAmerica Twitter: https://twitter.com/gma #GMA #BuffaloNY #Buffalo #PaytonGendron #MassShooting