atf examiner greg klees examined the extrusion marks made on the plastic insulation as it squeezed throughhe die during the manufacturing process. this process makes the wire its uniform size. >> those marks will be imparted on that plastic insulation for a number of feet before it changes dramatically. >> lined up on a comparison microscope, it was no doubt. the wire from both bomb sites came from the same source. >> in fact, that these were produced on the same forming die at the same plant. >> they also discovered both bombs used the same glue and the same cotton string. since both bombs appeared to be made by the same individual, this eliminated jimmy morris and phil ryan. they both had solid alibis for the second bombing. but why did these boys implicate themselves in the first place? >> they offered an explanation that they were doing this because they were playing this "dungeons & dragons" game. >> they really spent a lot of time wasting the time of investigators. >> i thought that was an incredibly stupid thing to do. >> then a witness came forward saying she'd seen a white male wa

process the scene and track the gun and look at the bullets and examine everything, that will be a slow process. >> all right, retired atf special agent jim cavanaugh. another shooting in vegas left two police officers and civilian dead this week. i'm joined on the phone by cliff shefter, he wrote about repercussions of these sessions and political role in lobbying groups on the hill. thank you so much for being here. what are your thoughts today after this most recent school shooting? >> first of all, my pleasure, thanks for having me on, ronan. my thoughts are that this is not going to stop. we know how to stop this and watched every other country high income country like us, most recently aus trailial in 1996 after the port arthur massacre who was on a similar path to us, they have not had one mass shooting since then even though they had 11 of them in the ten years preceding that. it's not a mystery. we have the national rifle association who in service of who their real clients are, which are the gun manufacturers that make millions off of selling military style rifles and military style weaponry to people, they don