After 15 days of testimony from witnesses for the prosecution, attorneys for admitted Boston Marathon bomber Dzhokhar Tsarnaev began to present their case yesterday afternoon. A day and two hours later, the defense rests, having called just four witnesses to the stand. Boeri and Cullen discuss Day 16 and the defense's limited focus in this phase of the trial - on portraying Dzhokhar as following the lead of his older brother Tamerlan.