command structure and all the members. and their code names. they're all identifiable. now we've got the whole story. now we can see everything. >> we saw guns, dynamite, ammunition, swastikas on the wall, and both me and my partner saw a mack 10 submachine gun which we knew had been the type of weapon used to kill berg. and we both said, you don't think they're stupid enough to have kept that weapon, do you? and we both said, we'll, we'd better find out. and the next morning i get a phone call from the firearms examiner in washington that said that is the gun that killed alan berg. >> how did you feel? >> total exhilaration. total. gotcha. talk about physical evidence. they kept this. this gun killed alan berg. >> here we are now chasing one crime after another and finally