Authorities knew Maine shooter was a threat but felt confronting him was unsafe, video shows
CBS News: Daniel Flannery, director of the Begun Center for Violence Prevention, Research and Education, cautioned that only so much about a police investigation can be gleaned from a few minutes of video. “There is always context, there is the issue of what is the training and protocol within the division,” Flannery said. “Violent behavior is unfortunately one of the most difficult things to predict.”