First Word: Pressure cooker bombs in Boston

Updated
An unidentified Boston Marathon runner leaves the course crying near Copley Square following an explosion in Boston Monday, April 15, 2013.
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

The FBI is asking the public for clues into the deadly Boston Marathon bombing that killed three and injured more than 170. Officials said the two shrapnel-laced devices that exploded Monday appear to have been packed into pressure cookers and then hidden inside backpacks.

msnbc’s Lawrence O’Donnell will anchor the show live from Boston tonight at 10pm ET. Here’s a look at the headlines we’re following now.

First Word: Pressure cooker bombs in Boston

Updated