Michele McPhee, author of Maximum Harm: The Tsarnaev Brothers, the FBI, and the Road to the Marathon Bombing joins Chris McCarthy to discuss the bombing.

McPhee, a columnist and correspondent for The Boston Herald, discusses how the Dzokhar and Tamerlan Tsarnaev detonated the bombs five years ago at the Boston Marathon, but that the U.S. government doubts that were the ones who built the bombs--and has no idea who actually did.

She delves into some of the deeper aspects of the case against the Tsarnaev brothers, and tries to figure out exactly how the two could have pulled off the bombings while supposedly already under the watchful eye of law enforcement.