frank figliuzzi, jim kavanaugh still with us right now. frank and jim, i'm struck by the fact as we watch this -- this is as much a rite of the american fall, start of the new school year as is the photo before the first day of school on the doorstep. send your student off and within days and sometimes weeks, there are then these headlines about school shootings. the surgeon general, of course, taking the unprecedented step earlier this year of declaring gun violence a public health crisis in this country. that, of course, is not unique to what happens on school campuses. obviously, those shootings get so much attention given the privilege in this country. four in ten americans say that they have -- live in a household with a gun. 32% of americans say they own one. of course, the right to ear arms is protected. the challenge is how to keep it out of the hands of those individuals, for whatever reason, may be dangerous and make the decision to use this on a school campus or anywhere else in their community where innocent victims are killed.

i want to bring in retired atf special agent in charge jim kavanaugh.o cover? it seems as though they don't stop. in this case, just at the beginning of a new school year. days into this new school year. here we have a high school on lockdown. what are some things officials are doing at this hour? >> jose, frank gave you a great assessment. he is always spot on on describing what's going on. just building on what he said. what the on-scene commander is doing what we call, locate, isolate and evacuate. the first task of officers, whether it's the patrol officers who arrive and go in in the triangle formation that we all learned for an active shooter, or it's s.w.a.t. who is following on their heels, they have to locate first the killer or killers. that's the first thing. then they have to isolate that person. that could be they have them in a gym, a classroom. they know where he or she is. then once they do that, they can decide that there's an area behind the officers that can safely be evacuated. the reason they have to isolate first is you can't evacu

back with us is lisa rubin and barbara mcquade, also jim kavanaugh.the scale of this investigation? >> there are two things that really stood out to me. one is that damien williams, the u.s. attorney, was confirming as part of their searches of combs' houses, they walked away not only with those three ar-15s that you are showing, but they walked away with images and videos of the so-called freak offs, the sex performances that combs orchestrated and directed for his own pleasure to the severe detriment of his victims. the other thing the press conference illustrated was that their investigation is ongoing. he said, combs did not do this all on his own. we are not done. this investigation is ongoing. during the question and answer portion of the press conference, he gave no further specificity about that, but left the door open to either additional charges against sean combs or potentially charges against others who are part of that group of people who empowered sean combs through the alleged racketeering conspiracy at the heart of this indictment. >>

jim kavanaugh is a retired atf agent in charge and hostage neglector and msnbc contributor.re's two big parts to this if we put them in buckets, and we see the press conference is ending after about 50 minutes, ken. let me start with what happened on july 13th. that had been deconstructed in the days and weeks following it, but what new did we learn here? >> i think two main never cohe instructed local law enforcement how they were supposed to protect that building, which the sniper ultimately used to get up on the roof and fire those shots. they never explained how they're supposed to do it. they never checked to make sure it was being done. that was a glaring failure. we knew the roof was unprotected. there's a dispute about who told what to who. there was body cam, i told the secret service the roof was unprotected. as it turns out, the secret service folks who did advanced planning never had a plan for the roof, never communicated it to local law enforcement. it wasn't protected. secondly, the big glaring error is because there were no local law enforcement officers in t