Summary: <p>The FBI is leading the investigation into explosions that killed three and injured about 140 people near the finish line of the Boston Marathon. A number of blocks in downtown Boston are being searched for clues. At the time of the blasts, the area was crowded with spectators and runners in what has traditionally been a day of celebration and pride in the city. In remarks last night, President Barack Obama pledged to put the full resources of the federal government behind the investigation. But many also warn not to rush to judgment. Diane and her guests discuss questions on the day after the deadly explosions in Boston.</p>
