Police say the 18-year-old gunman had a disturbing plan when he stormed into the Buffalo Tops on Saturday. They say the suspect may have been scouting the location back in March. Authorities interviewed the suspect’s parents, confirming he had written a 180-page racist rant. Last June, the suspect had also previously run into law enforcement when he allegedly threatened to carry out a school shooting but was released after being given a mental health evaluation. The Buffalo community is mourning the ten victims, including Tops security guard Aaron Salter, who was killed trying to guard the store. » Subscribe to NBC News: http://nbcnews.to/SubscribeToNBC » Watch more NBC video: http://bit.ly/MoreNBCNews NBC News Digital is a collection of innovative and powerful news brands that deliver compelling, diverse and engaging news stories. NBC News Digital features NBCNews.com, MSNBC.com, TODAY.com, Nightly News, Meet the Press, Dateline, and the existing apps and digital extensions of these respective properties. We deliver the best in breaking news, live video coverage, original journalism and segments from your favorite NBC News Shows. Connect with NBC News Online! NBC News App: https://apps.nbcnews.com/mobile Breaking News Alerts: https://link.nbcnews.com/join/5cj/breaking-news-signup?cid=sm_npd_nn_yt_bn-clip_190621 Visit NBCNews.Com: http://nbcnews.to/ReadNBC Find NBC News on Facebook: http://nbcnews.to/LikeNBC Follow NBC News on Twitter: http://nbcnews.to/FollowNBC Follow NBC News on Instagram: http://nbcnews.to/InstaNBC #Buffalo #NewYork #SupermarketShooting