Police videos, 911 calls, and documents are revealing new details about the man who opened fire in a New York City office building last week, killing four. NBC News’ Erin McLaughlin reports. For more context and news coverage of the most important stories of our day, click here: nbcnews.com » Subscribe to NBC News: nbcnews.to/SubscribeToNBC » Watch more NBC video: 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: apps.nbcnews.com/mobile Breaking News Alerts: link.nbcnews.com/join/5cj/breaking-news-...