when you hear officials say that it is genuine concern because they have seen this grow over the course of the last 48, 72 hours from one target to multiple targets, and let's be frank, the perpetrator or perpetrators are still at large so this manhunt under way and they want to find him or her or them before they can attempt to strike again. >> jim sciutto, thanks so much. i want to go straight to our senior justice department correspondent evan perez and you have some new information just coming in about these bombs. >> reporter: well, that's right, jake. i mean, the fbi took the extraordinary move today of publishing a picture of one of those packages, and one of the things that's already happening is that the fbi lab in quantico has been able to examine some of the initial devices,the first one, of course, showed up a couple nights ago at the home of george soros, and they've noticed it contained a sort of sulfur material.