LEMON: There is new information into CNN now about the bombings here in Boston. We are being told by an official with knowledge of this investigation. Our Fran Townsend, our security analyst, saying that a pressure cooker lid similar to this one, a pressure cooker lid, believed to be used in those bombing at the Boston Marathon found on a roof not far from the marathon site -- not far from the finish line. That will be used as well as other information, other materials found to piece together exactly what happened. We're also being told that the remains of the pressure cooker found at the scene there are pictures now that are coming in along with a shredded back pack and what appeared to be metal pellets or ball bearings strapped of at least one pressure cooker, nails, a nylon bag, found at the scene were sent to the FBI's national laboratory in Virginia where technicians will try to reconstruct the devices and the agent leading this investigation told us this information on Tuesday. These pieces suggest that each of the devices was a six-liter -- six liters about 1.6 gallons in volume. That's according to a Boston law enforcement source. And the recovered parts included part of a circuit board which -- which might have been used to detonate a device. Again that's the information coming in to CNN now from sources, who are close to this investigation. They're going to look at timers, they're going to look at circuit boards, they're going to look at all of the part that may have been used in this ball bearing, BBs, nails, anything found at that scene to try to piece together exactly who did this and how they did it. Again, CNN has found, has learned, that a pressure cooker lid, believed to be used in one of the explosions at the Boston Marathon found on the roof of a building right across from the finish line. More information right after the break.
Exclusive: Pressure Cooking Lid Found on Roof