MS NOW

First Word: Pressure cooker bombs in Boston

The FBI is asking the public for clues into the deadly Boston Marathon bombing that killed three and injured more than 170.

An unidentified Boston Marathon runner leaves the course crying near Copley Square following an explosion in Boston Monday, April 15, 2013. (AP Photo/Winslow Townson)
An unidentified Boston Marathon runner leaves the course crying near Copley Square following an explosion in Boston Monday, April 15, 2013.AP

Sarah Muller