Investigators Find Circuit Board Believed Used as Detonator in Boston Marthon Bombing

At the Boston Globe, "Investigation of Boston Marathon bombings continues: Circuit board found near site of blasts."

Investigators combing through the scene of the deadly Boston Marathon terrorist attack have recovered a circuit board that they believe was used to detonate the bombs, according to an official briefed on the investigation.

Investigators have also recovered components of the bombs, enabling them to determine that they consisted of two 6-liter pressure cookers packed with nails, ball bearings, and other metal. The makeshift bombs were placed in black duffel bags, the official said.

The one that exploded first was placed on the ground on Boylston Street, across from the finish-line viewing stands where dignitaries, including Governor Deval Patrick, had been sitting earlier. The second bag was placed on the ground about 75 to 100 yards down the street, outside the Forum restaurant at 755 Boylston, according to the official.

The bombs, detonated about 12 seconds apart, killed three people and injured 176 others, including 17 who are still in critical condition. The attacks created a scene of bloody carnage near the finish line of a race that is a colorful rite of spring and draws runners from around the world, who are cheered to the finish line by happy crowds.

More at that top link, and at the Globe.

And see the Wall Street Journal, "Boston Bomb Clues Surface: Officials Believe Lethal Devices Built From Pressure Cookers; Scene Is Scrutinized."