Boston Marathon Explosions

How do you track down a bomber?  When the FBI is involved, there's some high-tech detective work that can help.

FOX's Catherine Herridge reports from Washington in our ongoing series on national security:

FBI Lab - Quantico

Securing America.

The Senior FBI Agent in Boston, Richard DesLauriers, says bomb components are being shipped to the FBI crime lab in Quantico, Virginia, where technicians will reconstruct the devices.

(DesLauriers) "Among items partially recovered are pieces of black nylon, which could be from a backpack, and what appears to be fragments of BBs and nails, possibly contained in a pressure cooker device."

Reconstructing the bombs will help investigators identify where the bomb parts are from and, possibly, who bought them - this is referred to as the bomb's "unique signature".

In Washington, Catherine Herridge, FOX News Radio.

CLICK HERE for more on the bombs at the Boston Marathon.