The Washington navy yard were President Obama is set to speak at a memorial service later today twelve killed by a deranged navy contractor. Here's ABC's Pierre Thomas. -- For six weeks -- and Alexis... See More
The Washington navy yard were President Obama is set to speak at a memorial service later today twelve killed by a deranged navy contractor. Here's ABC's Pierre Thomas. -- For six weeks -- and Alexis exhibited increasingly bizarre behavior. In short he was a ticking time bomb but no -- seemed to detect August 4 a disturbing confrontation at Norfolk international airport. Unprovoked Alexis accuses an Alabama family of mocking him. -- behavior is something wasn't right with him. No absolutely airport security intervened but since everyone on their way no more questions -- August 7 only three days later in Newport, Rhode Island. Alexis tells police that -- hearing voices and under constant surveillance what's more he's said his tormentors are bombarding him with a microwave machine. New port authorities -- naval station police about the strange behavior. But the -- was never passed up the chain of command. There should have been some kind of mental health assessment done. -- to determine. The severity of these hallucinations. August 23 Alexis goes to a VA hospital in Rhode Island and another here in Washington on August 28. Complaining of insomnia. On both occasions they give him sleeping medication and ask if he's a danger to himself or others he says no. They take him at his word and last Monday a -- goes to work at the navy yard. Only to explode. In an episode. Of wanton violence. For this week Pierre Thomas ABC news Washington. General -- Peter -- -- joins us again along with. Mark Barton who lost his seven year old son Daniel. At -- sandy hook school mark is now a member of the grassroots group sandy hook promise and ABC's chief medical editor doctor. Richard best -- I wanna start as -- sit here in the shadow of the navy yard in the very building where twelve people lost their lives. Earlier this week with with you doctor -- You called this. We were talking a little earlier approved. -- surprise and yet. Nothing has been done I mean he's seen in public health there's this term predictable surprise it's something that was totally foreseeable. But when it happens we act like how could this have happened -- -- we're we're surprised by that. But events like this are preventable if you understand what the root causes are. But as a nation we're not taking those steps to really understand that so we're going to see this again and again and again. Mark I -- know sitting here has to be somewhat emotional for you seeing another man shooting. The reaction of the country the reaction of the media even the reaction of the president. Seems so different. It does then I would hope that we are not reaching a place of complacency. That we can't accept this as part of our culture. There's with with a similar promise and -- just my own personal position there are so many things that that we can do. We will continue to work in a holistic. Better. I'm on a lot of issues to try to address this sandy hook -- certainly trying to do those things perhaps through. Just general Crowley who -- we should say that you dealt as vice chief of staff the army with mental health issues all the time the terrible epidemic. Of suicide. One of the things I know you tried to do. It's trying to get commanders to tell people who are having mental health issues -- posttraumatic stress to remove themselves from the weapons. From their personal weapons. And you got pushed back. What we we did but congress' -- fix that by taking language -- build admitted. Possibly force to implement. What we were trying to do yet admiral Mike moment former chairman of the Joint Chiefs of Staff -- had read a lot. Of the literature that indicated that if you just recommended to a person who was at risk -- at high risk for suicide. That you separate from yourself from your personal weapon. A suicide rates go down so -- added he recommended to the services that we implement them. -- there was language and a national defense authorization bill that did allow us to collect that kind of information. -- on soldiers just last year congress corrected that. But just think what it would mean if we could take that in applied it to the 38000. Suicides that are committed in this country every single year. And you you are still dealing with with mental health issues with your organization one mind. That is doing a lot of research into the brain and like all of you to talk about what really just happen here how do you tackle this as a nation and he did. This CDC back in the 1980s had a very robust program that was looking at gun violence looking at issues of mental health what are the drivers about gun violence. Then there are -- around 1990. The congress at the behest of NRA cut off that funding. And here we are 25 years later would we still don't have the answers of what -- the best interventions to it to stop this problem. It ended after -- even approach the problem. It I mean the diagnosis to treatment all of that doesn't seem very kind. -- it's it's -- -- diagnostics are horrible in this particular if you take posttraumatic stress. He would DSM four which is a psychiatric manual used to go it had provided diagnosed -- basically ask the person seventeen questions. There are no blood -- markers there's no X -- there's that there are no other kinds of tests except. You ask the person questions and based on their answers you make a determination on whether or not they have posttraumatic stress or -- we've got to get beyond that. -- we also have to get to the point where people have access to services as bad as the tests are. If you look at the provision mental health services -- health party bids for people. Who have a problem to get -- scene. -- one of the things about health reform is to make sure that mental health issues. Are treated the same ways physical problems that's -- I am sure that that's going to be part of the part of the solution. -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- To get them the treatment that they need we I ran into problems in the military with certain accepted. Treatments for different mental health issues not being accepted by the insurance company. And and then they'd go to the VA and get different treatment -- we're gonna -- I -- -- I think early intervention is critical component to this and and now. There we applaud the efforts of senators I and baggage for. For pulling this bill out you know the one from -- -- Alexander of mental health bill. It -- 95 to two in the senate in April they want to bring that out as a standalone bill. And -- senator Richard Blumenthal supports that he said this is a good place to start with a common ground where we can all kind of agree on this and there are a lot of things of that bill that we support. As far as. Identify children that are at risk. Training the teachers to be able to identify them and -- -- hoping to get those services that they need at an early stage. One thing when we look at the shooter from the navy yard is judgment there's just judgment that was missing -- all these people who who came in contact with. You have to look at it from a systems point of view and look at -- the big problem of gun violence of of these mass killings and say. What can we do to stop these I want to thank you all for being here sorry to cut -- short a great conversation.
This transcript has been automatically generated and may not be 100% accurate.