James Alan Fox is the Lipman Family Professor of Criminology, Law and Public Policy at Northeastern University. He has published 18 books, including “Extreme Killing: Understanding Serial and Mass Murder.” As a member of its board of contributors, his opinion column appears regularly in USA Today. Before that, he wrote a bi-weekly column in the Boston Herald and the Crime and Punishment blog for The Boston Globe. He has also served as a news analyst for NBC/MSNBC. Fox headed the investigation of the Capitol Hill massacre for the Seattle Police Department, served on President Bill Clinton’s advisory committee on school shootings and has been an expert witness in several civil actions stemming from mass shootings. He is currently directing a three-year project on mass public shootings funded by the National Institute of Justice and is one of the principals in producing The Associated Press/USA Today/Northeastern University mass killing database.