They say to catch a criminal, you have to think like one.  That’s an approach the Boston Police would like to try, by implementing a new software program that would scan social media platforms.  The goal is to uncover threats to the public safety when they’re just being hatched.  Jim Braude (@jimbraude) talks to people on both sides of the issue:  Former Watertown Police Chief Ed Deveau (@EdwardPDeveau), about why this could help law enforcement in the 21stcentury;  and Kade Crawford (@onekade), director of the Technology for Liberty Program at the ACLU of Massachusetts, who is concerned this approach could be an invasion of privacy.