of -- two of these ieds. one that was being mailed to maxine waters, the congresswoman. and another one that was being mailed to barack obama, the former president, had his dna. so they were able to match it to records they already had. they also found a fingerprint in one of the ieds being sent to maxine waters. again, they were able to compare that to fingerprints that he had from his previous arrest record. so the fact that he had a wrrap sheet a mile long was extremely helpful. >> as soon as they found the fingerprint on the package sent to maxine waters, they apparently had their guy pretty quickly. it was not hard to find him. shimon, what have we learned about these improvised explosive devices, as christopher wray calls them? how were they made, and were they armed? >> yeah, so the fbi director explained at the press conference and also in the court documents, basically, the way they're described, they're six