Fmr. ATF Acting Director Mike Sullivan says total number of bombs potentially tells how long the Boston Marathon attacks were being planned

This morning Bostonians are still reeling from the shock of a terror attack in their city. On Monday three people died in the twin bombings at the Boston Marathon including a 8-year-old boy who came to see his father run. The FBI is now leading the investigation into the twin explosions that left more than 150 others injured. This morning Former ATF Acting Director Michael Sullivan joins a special edition of “Starting Point” to weigh in on the latest.

Right now FBI and ATF agents are “trying to capture all the forensic evidence that’s going to be useful to them to determine … how sophisticated the device was [and] whether or not they’re seen similar devices in the past,” says Sullivan.

The former U.S. attorney says while some may view the leftover pieces of the bombs as rubble, the experts “who go in there after the post blast investigation look at it as evidence.” He adds that evidence can also be drawn from the undetonated bombs that were reportedly found at the scene.

Sullivan says the total number of bombs potentially tells “how long the person has been planning the event.” He adds that the component parts will be traced to see if any information can be gathered about the bombs’ place of origin.