MS. DIANE REHMThanks for joining us. I'm Diane Rehm. Yesterday, a gunman opened fire outside a Jewish community center and at a nearby retirement community in suburban Kansas City, killing three people. That incident occurred just days after a mess stabbing at a Pennsylvania high school and another shooting at Fort Hood in Texas. A year after the Boston Marathon bombing, we talk about how these episodes of violence in public places affect our sense of security.

MS. DIANE REHMWith me, psychiatrist Liza Gold of Georgetown University, Bruce Shapiro of Columbia University, and threat and risk assessment expert Caroline Hamilton. I do hope you'll join us, 800-433-8850. Send us your email to drshow@wamu.org. Follow us on Facebook or Twitter. Welcome to all of you. Thank you for being with us.

DR. LIZA GOLDThank you for having me, Diane.

REHMGood to see you all. I wonder if I could start with you, Bruce Shapiro. We know that mass shootings are up, even as overall violent crimes are dropping. What's going on here?

MR. BRUCE SHAPIROWell, it's interesting, you know. It's actually clear that mass shootings are going up. There's a lot of argument among statisticians about this. It's true that shootings involving, oh, 12 or so people seem to be up, but, on the other hand, if you bump it up just a little more and you say, as the FBI does, I think, shootings of 14 to 20 people, those numbers have remained pretty stable over the last 25 years or so.

MR. BRUCE SHAPIROIt's not so much the increase, I think, as it is the way in which these mass shootings strike at our sense of safety. And I think that -- and because not only do they strike at our sense of safety, but the sort of political hotwires of guns and mental health and so on are connected in them. We are more aware of them in some ways than we ever have been. The dividing lines in our society are symbolized and represented by these mass events, even though they're often very different from one another, and that might be something to talk about.

REHMBruce Shapiro, he's executive director of the Dart Center for Journalism and Trauma at Columbia University. Turning to you, Dr. Liza Gold, she is clinical professor of psychiatry at Georgetown University Medical Center. In your mind, what do these incidents imply about the state of our society and its sense of security?

GOLDWell, you know, as we've talked about before, mass shootings, mass stabbings are a very low base rate incidents. They're actually very infrequent relative to the amount of violence, especially gun violence, that occurs in this country. The morbidity and mortality of gun violence is huge, but the mass shootings only represent a very small, small fraction of that problem.

GOLDHowever, because they are so sensational in the sense of them happening, A, in public places, B, out of nowhere, C, people who have no connection with the shooters often or usually, it makes us all, you know, very anxious to sort of think, that could be me, that could be my spouse, that could be my kid. You know, bombings -- for example, we were talking about the Boston bombing. Bombings in this country are relatively rare.

GOLDAnd yet when they happen, they are, you know, profoundly affect all of us. And so the question then, in some ways, is, why did these relatively rare, low base rate events have such a powerful effect on all of us and our own sense of safety in our world? And I think that's a very interesting question, and I think it brings us -- I have a theory as to why that is.

GOLDAnd I think that when people feel powerless about things that are potentially dangerous, they obviously become more anxious. And because we are not addressing the problem, particularly of gun violence in this country in a constructive way, we're all stuck. We're all paralyzed, and that paralysis increases the sense of anxiety that these incidents cause.

REHMAll right. And turning to you -- Caroline Hamilton is in Fort Lauderdale, Fla. She is a threat and risk assessment expert and president of Risk and Security LLC. I've been referring to a recent survey by Mother Jones magazine which indicates that there have now been at least 62 mass shootings in the past three decades. This has happened even as the nation's overall violent crime and homicide rates are dropping. Caroline Hamilton, how do you assess that threat of risk for the general population?

MS. CAROLINE HAMILTONThanks, Diane. We've done some original research on that that's shown that there had been a huge increase in these mass incidents, especially since 2005. And not only the number -- and I'm using FBI statistics here. And they classify an active shooter as an event where three or more people are injured or killed.

MS. CAROLINE HAMILTONAnd if you look at those numbers, you'll see that they've doubled and tripled since 2005 in the number of incidents per year and also how many people were injured or killed in each incident. And some people link that to expiration of the assault weapons ban in 2005 because that's when these numbers really started going up.

REHMAnd, of course, it's not just guns as we know from the stabbing incident at a high school the other day, Caroline.

HAMILTONThat's right. These mass casualty events can happen in the -- you know, you can run into a crowd of people yesterday and, you know, kill five people. But, again, as Liza said, the number -- the actual number compared to other events that could happen is relatively low. So odds of dying of a heart attack, you know, one in six. Odds of dying in an air travel accident, you know, one in 20,000. Odds of dying in an earthquake, one in 148,000.

HAMILTONAnd these are all from the National Safety Council. But, again, I think I have to agree with Liza that it's the randomness of it that's frightening, even though we do know a lot about these active shooters. We know that most of them are male. We know that they shoot without any motive, really. They just want to go and shoot. And that's what happened in TSA. That's what happened in Fort Hood, you know. That's what, probably, what we're going to find out about the Franklin Regional Middle school stabbing -- or high school stabbing.

REHMAnd, Bruce Shapiro, you yourself have actually been a victim of violence in a public place. Tell us about that experience and how it has affected your views.

SHAPIROYeah. It's now a long time ago. Twenty years ago, I was sitting in a cafe near my home in New Haven on a quiet summer night when a man sitting a few tables away, whom I had never met, had a psychotic episode. Profoundly mentally ill individual pulled out a very big hunting knife and stabbed seven people, including me. None of us died, fortunately. All of us were quite badly injured. It was one of those events that took off in the news media, very much the way the Pennsylvania mass stabbing has and the way mass shootings do.

SHAPIROIt happened on a slow news night in August. Perhaps that's why or perhaps it was the spectacular and sudden nature of the event, but it certainly had a profound effect not only on those of us who were injured but on the entire community of New Haven and many of the folks connected to us in various ways.

REHMWhat kind of effect, Bruce?

SHAPIROWell, I think there were some -- a few different things. Certainly, on a personal level for me, I was and am a journalist, and it led me to really focus very much on the role of violence in American life and American politics and how we deal with the intersection of issues like violence and guns and mental health, all at the same time, and politics and how that plays out in politics and the role of victims in American politics, which is a very interesting issue.

SHAPIROIn the community, people were deeply shaken. This incident got a lot of attention, and, in a way, it was disproportionate. A couple week later -- actually less than two week later, a young woman in her early 20s, woman named Rashonda Crenshaw (sp?) was driving through a neighborhood just a mile away from where I was stabbed, and Rashonda Crenshaw was shot and killed randomly.

SHAPIROIt was a drive-by and a stray bullet. It was a story for about three days and then went away. The story of the mass stabbing took on a life of its own. And indeed, as my assailant went through the mental health process over the years, as recently as last year when he was released, it remained a big story. Now, that, on the one hand, is interesting and, on the other hand, is unfair to many individuals.

REHMBruce Shapiro, he's executive director of the Dart Center for Journalism and Trauma at Columbian University. Short break, right back.

REHMWelcome back. Joining me now by phone from Plattsburgh, N.Y., Thomas Nolan. He's chair of the Department of Criminal Justice at State University of New York at Plattsburgh. Thanks for joining us, sir. I know you served as a City of Boston police officer for 27 years. Give us your thoughts on tomorrow's anniversary of the Boston Marathon bombing.

HAMILTONWell, I've seen, for the first time, public officials referring to the event as 4/15, in reference to the 9/11 attacks obviously. I guess a concern that I have, as we're in the final week before the next running of the marathon will be a week from today...

REHMRight.

MR. THOMAS NOLAN...and police officials have publicly, in their attempt to assure the public that this will be a safe event for spectators and for families and for runners, have walked, I think, a difficult line and a tightrope in trying to assure people that this will be a safe event while at the same time maintaining what's sure to be an unprecedented police presence there.

MR. THOMAS NOLANAnd we should be concerned, I think, because they've made public announcements that they are going to search people without warrants who are carrying backpacks in or around the finish line of the marathon. And this is something that we ought to question, I think, given even in light of what went on last year and that horrible tragedy. In the aftermath of that bombing, we saw for the first time, in my memory, in my experience in policing, where police went door to door and conducted warrantless searches.

REHMHmm.

NOLANOn the heels of that, we're seeing that what they're telling us is going to occur is that people who are carrying backpacks near the finish line of the race are going to be searched.

REHMYeah.

NOLANAnd they're going to be searched without a warrant. And I don't know what the legal basis or justification for these searches are.

REHMBut I find myself wondering, considering the tragedy that did occur last year, whether this is kind of a new normal, and we just have to get used to it in order to stay safe. What do you think, Tom Nolan?

NOLANI don't think that we should get used to this new normal. I don't think that surrendering our constitutional rights and our civil liberties in order to ensure that we have a safe event is a step or a direction that we want to go into. I think that the police are not going to find any bombs or any kind of explosive devices in backpacks that they search. If someone is intent on creating havoc and committing an act of atrocity at a public event like this, they're going to do it one way or the other.

REHMAre you saying that there is no way to be more proactive against these kinds of attacks?

NOLANI think the proactivity needs to occur at the front end of these kinds of events in intelligence gathering and information sharing. And I think what we have learned in the aftermath, for example, of the Boston Marathon bombing is that there was a failure on the part of federal, state, and local law enforcement agencies to share intelligence, to share information.

NOLANSo the Tsarnaev brothers, for example, were on the radar of the FBI. And that information was not shared with local law enforcement authorities, as far as I know, in spite of the fact that we have, at my last count, 74 state and major urban area fusion centers that were established in the aftermath of the 9/11 tragedy under the umbrella of the Department of Homeland Security where I worked for a year-plus, for the specific purpose of sharing information. Now, that didn't happen.

NOLANAnd I think that this intelligence gathering apparatus that is huge in the United States is, I think, at least in part, the solution to getting out in front of incidents that might occur rather than having this reactionary kneejerk -- I'm going to suggest hyper-exaggerated -- response in a massive police presence, no doubt with long guns. And we're going to see police officers in military uniforms. We are seeing in the aftermath of 9/11, a move decidedly and pointedly away from community policing strategies and the philosophy of community policing into the homeland security era.

REHMAll right. I want to bring Caroline Hamilton in here. Talk about the difference between being proactive, as Tom is suggesting, and somehow being retroactive in security practices. Talk about his concerns over perhaps unlawful investigations.

HAMILTONWell, I think that when you get where you're relying on intelligence that you may or may not be getting, that's a valid concern. But, for me, what I see missing in all of these recent events is that there's just -- there's not a minimum level of security that's in place. Yes, they have -- they can stop people and look at their backpacks. But why not have -- you know, I just looked that they're going to have an extra, you know, 3,500 policemen. They're going to have 100, you know, contact points along the Boston Marathon route.

HAMILTONAnd they have -- the FBI's already said that they have no specific intelligence indicating any kind of threat. So, like they do in large football stadiums, you know, what's wrong with having some access points to the route so that you can have -- you can -- they can take either x-ray, metal detect, or take a cursory look in a backpack or a large bag when you're in the event area? And then you're not going to get these standard searches. But those only come up when they don't have the good security at the beginning.

HAMILTONSo reactive security is when you wait until something happens and then you go try to fix it. You know, you take people to the hospital. You have the great emergency responders. All these things happen. What you need is security ahead of that in a proactive state where it's risk-based security. So you analyze all the risk information you have. You put controls in place that would mitigate the risk or prevent things from happening. And then that's where you're going to get your security without having to violate your constitutional rights.

REHMAll right. But here you have the shootings yesterday at Jewish-related locations in Kansas City. I mean, what could be done to prevent some random shooter from acting out? This person is allegedly a former Grand Dragon of the Ku Klux Klan. What do you think of that, Bruce?

SHAPIROWell, look, you can have all kinds of intelligence, and you can have all kinds of barriers. As, you know, airport -- we know from airport security, there are ways of not only finding stuff on people but discouraging would-be assailants by the number of barriers. And if you go to, you know, Britain or go to Northern Ireland during the troubles there, they learned a lot about controlling access to city centers. You can do all that.

SHAPIROI think it's really much more important though to think hard about the different kinds of people and the different kinds of very angry individuals who commit these kinds of acts. I mean, there's a big difference between the apparent shooter in Kansas City who is an anti-Semite and like Anders Behring Breivik in Norway is motivated by a kind of paramilitary fantasy of himself as carrying out hate -- same thing as the Tsarnaevs.

SHAPIROBig difference between that and someone who is profoundly mentally ill like Cho, the shooter at Virginia Tech, and a big difference between them and what happened at Columbine High School. There's a lot we still don't understand about Adam Lanza at Newtown. These are different kinds of people.

SHAPIROAnd I think that until we, as a society, begin to stop simply responding with fear as if all of these incidents are the same, and instead say, how are we as a society contributing to lack of safety? Are we having all the mental health services available and destigmatizing getting help for people who need it in a way in which we should? That's not going to stop everybody, but that stops a lot of people. Are we doing things to keep guns out of circulation?

SHAPIROYou know, it's so interesting the number of people carrying weapons to school has actually gone way down. It's been cut in half in the last couple of decades, and yet there are so many guns out there that these incidents can still happen.

REHMLiza.

SHAPIROImagine what would've happened in Pennsylvania in Murphysville if the young man there had been carrying a gun instead of two knives?

REHMIndeed.

SHAPIROYou would've had 20 dead people.

REHMLiza Gold.

GOLDAnd I believe that what Bruce just said is actually the thought that occurred to many, many people. And I think that we need, as a society, to understand that violence, particularly gun violence, these other kinds of violence as well -- but particularly gun violence is a public health issue -- and address it from all perspectives as a public health issue. And one of the reasons I say that is because, when you look at a public health perspective, you're looking at intervention and prevention on multiple levels in a collaborative way.

REHMBut isn't it interesting that the nomination of the surgeon general has been held up because he once talked about gun violence as a public health issue?

GOLDYeah. And I think we need to raise awareness more and more in this country that it's not about -- that a public health approach to managing the morbidity and mortality associated with violence, particularly gun violence, is not about being anti-gun, OK. The law is clear. The constitution is clear. The Supreme Court has made it clear. Guns are -- owning firearms is a constitutional right. That doesn't mean that we can't do better in managing the morbidity and mortality, the number of children who get killed accidentally.

GOLDMy understanding -- and again this is just based on what I heard on media reports -- was that the reason that the young boy didn't have a gun -- his parents didn't keep guns in the house. Well, that is such a huge risk factor for teenage suicide. If you have a kid in your home who is having any kind of mental health problem, or even an adult really, or a substance abuse problem, a public health message -- get the gun out of the house.

REHMDr. Liza Gold, she's clinical professor of psychiatry at Georgetown University Medical Center. And you're listening to "The Diane Rehm Show." Here is an email from Emma. She says, "If the media had daily reports about every car accident that killed one or more people, wouldn't we all feel more scared about driving, even though most of us feel no fear when we get into a motor vehicle? The chances of getting seriously injured or killed while driving is probably the greatest risk most of us take each day. Discuss the role of the media in creating fear and obsessing about violence." Bruce Shapiro.

SHAPIROComplicated issue. I mean, look, these mass casualty events, these mass shootings and stabbings and bombings are big disruptions in the social fabric. They are big events. They are big stories. And there's no question that it's the job of journalists to cover them. That said, I think the way in which we cover them and immediately crank up the sort of 24-hour anxiety alarm, on cable TV in particular, leaves a lot to be desired and does, I think, impede rather than help clear thinking about what's going on. I think we could do much better.

SHAPIROI also think that the kind of core point of your listener's email of the proportional risk of different events is crucial. Not so much -- I'm not thinking so much about car accidents as I am thinking about intimate partner violence, childhood exposure to violence, which is a major public health problem and a major contributor to violence in our society.

REHMDr. Gold.

SHAPIROIt happens much more often.

GOLDWell, we, you know, as human beings, right, we do risk assessment on a little minute personal level every day. And most of us, in order to live in a society with other people, have to utilize certain amount of denial just to get through the day. So I get in my car, and I'm not going to die in a car accident today. I get in my car every day thinking that, well, of course, you know, things happen...

REHMCould be.

GOLD...and it could be. If I thought that every time I was going to get in my car, I probably wouldn't get in my car. But we learn to live with and accept that there's a certain amount of morbidity and mortality associated with driving, which is a necessary -- in our society, it's part of what -- you can't function very well in many places in our country without being able to drive. The same can't be true -- said of violence.

GOLDAnd it's interesting to me that we live in a similar kind of state of denial about the huge incidents of violence in this country that we accept without really thinking very much about it or doing risk assessments about it. And every once in a while, that bubble gets punctured by these sensational events. And what I would say is that, you know, all of these events are tragic.

GOLDThere's no question about that. But I think that, as a society, we need to step out of our denial a little bit more about violence. We made cars safer. You know, and we need cars. You can argue, you know, should they be gas or electric or whatever you want to argue, but most people need cars to manage functioning in this society. We -- do we need this level of violence? I don't think anyone would say that we do.

GOLDWhy then do we accept, you know, how many children are shot, how many people die? Thirty-thousand people a year die from gun violence alone in this country. If that was an infection or a food poisoning outbreak, there would be a public outcry like no one would believe. And if the CDC wasn't doing something about it or the government, people would be outraged.

REHMDr. Liza Gold, she is a clinical professor of psychiatry at Georgetown University Medical Center. We'll take just a short break. And when we come back, all of our guests will respond to your comments, your questions. Dr. Gold, Bruce Shapiro, Caroline Hamilton and Thomas Nolan are all with us.

REHMAnd we'll go right to the phones first to James in El Paso, Texas. Hi. You're on the air. Go right ahead.

JAMESHi, good morning. I have a statement and then a question for Bruce.

REHMGo right ahead, sir.

JAMESYes. The statement is, would you agree to differentiate the difference of the events such as the Boston Marathon, the Super Bowl and airports versus the more isolated events like, you know, an Adam Lanza shooting or a school shooting? And then my actual question is, besides giving up your constitutional right of privacy, what else do citizens gain to lose if they're involuntarily searched at major events, such as what I listed in previously?

REHMAll right, sir. And, Tom Nolan, why don't you take the latter part of that question first?

NOLANWell, I think, slowly, we begin to see an erosion of civil rights and constitutional protections because, if the police at a public event are going to search, for example, backpacks, where does it stop? Are they going to search shopping bags? Are they going to search a briefcase? Are they going to search a suitcase?

NOLANWe didn't -- when we don't question the police -- and I'm not suggesting that it's entirely outlandish that they engage in this practice. But when we don't question them, I would argue that we forfeit the right to do so the next time they take an incremental step in violating our constitutional rights. So that's the price that we pay.

REHMAnd, Bruce, why don't you comment on the first part?

SHAPIROWell, look, I think each of these events has been different. What they have in common is a lot of people being killed or injured. What they have in common is the exceptional anger of the assailants, which comes from different places, sometimes from psychosis, sometimes from politics, sometimes from life events and/or maybe just evil sometimes. And they have in common that these are -- they're very emotional events that strike at our sense of what is a safe society. Now we can use that to ratchet up the fear thermometer. And it's interesting.

SHAPIROI was thinking about this incident back in 1994. I remember getting really furious when I turned on the TV a few weeks after this mass stabbing in which I was injured, and there was a story on the news about a three-strikes bill in the Connecticut legislature, one of those tough-on-crime bills. There was what in the news business we call B-roll footage being used to illustrate this news story. And it was footage of me being put into an ambulance, a story that had nothing to do with tough-on-crime or anything else.

REHMInteresting.

SHAPIROWe ratchet up fear and use it for political ends. And...

REHMAll right. And here is an email from Leslie, who says, "I disagree with the panelist who said it's the randomness of killings that upsets us so much more than accidents in cars, planes, et cetera. It is the fact that the act is perpetrated intentionally by another human being. Death by accident is far less horrible to us generally than death at the hands of another human being." Liza Gold.

GOLDThat is true. And I would say that that is a very big piece of it in the sense that, for example, studies have demonstrated that the incidents of post-traumatic stress disorder tends to be higher after an event -- a trauma that has been orchestrated by a person than a natural disaster, such as an earthquake or a hurricane.

GOLDAnd there is the sense of, is there somebody out there that wants to do me harm? That is behind some of that as well. Nevertheless, it certainly is true that, again, as a society, we accept a certain amount of human violence that happens not in these sensational ways but in very casual ways on a daily basis without questioning why. Why do we accept this as part of the fabric of our lives?

GOLDMy belief is that if we can start to become more conscious of the ways in which we accept this violence and start to intervene in preventative ways -- and, again, to use an example, smoking, seat belts, et cetera -- if we can intervene in those preventative ways, we can reduce the incidents of the manmade violence in the similar ways that we reduce the incidents of morbidity and mortality associated with smoking, associated with not using clean water, associated with automobile accidents.

REHMAll right. Let's go to Jim in Berrien Springs, Mich. Hi, there. You're on the air.

JIMHi, Diane. Thanks for taking my call.

REHMSure.

JIMI have a question. I have an adult son who's in jail right now, charged with a violent act. At the time of his act, he was on six different psychoactive medications, each one of which has been linked to violence by way of research and also the medication protocols that are given out by the pharmaceutical companies themselves. I'm an accolade of Dr. Peter Breggin, who's written the book, "Toxic Psychiatry" and "Medication Madness." I really wish you could have him on your show sometime.

REHMI've had him on the show, sir. Go right ahead.

JIMOK. Is anybody thinking along that line? So many of these acts of senseless violence seem to be linked to people who are on psychoactive drugs and medication, and even the suicide rate in the military. Now, you know, I'm a retired military man. And when I was in the service, it was almost a stigma to be medicated. These days, it seems like that's one of the ways they use to keep them in the field. But the bigger question is, is your panel thinking about that?

REHMSure.

JIMAre people looking at that?

REHMAll right. Dr. Gold?

GOLDWell, this is an area that comes up every time we have this conversation about whether some of this or most of this violence is being fueled by psychiatric medication. And this is a hot-button topic for a lot of people. And it's much broader than I could possibly go into right now. I will say that there is a group of individuals who do seem to have a higher incidence of violent behavior associated with serious mental illness.

GOLDPeople who have serious mental illness tend to be treated with psychiatric medications so that it's hard to tell, in many cases, whether it's the underlying illness that is propelling the violence or perhaps a reaction to the medication.

REHMAll right. To Lee in Houston, Texas. You're on the air.

LEEHello.

REHMHi.

LEEMy name is Lee. I was the first reporter on the scene to the first of the modern shootings, which was the Killeen Luby's massacre in 1991.

REHMHmm.

LEEIt was the largest shooting since the San Ysidro shooting. And I followed it since then. I'm not longer a reporter. I'm in IT risk and security and also do disaster planning. A couple points, these shootings will never trigger any kind of gun control. Within weeks after the Luby's shooting, there was a gun control vote in Congress, and it failed. It's just not practically going to happen. It's just not.

LEEAfter the Connecticut school shooting, which you would think would have triggered some legislation, I started -- I put together an active shooter training class for people, represented the company I was with at the time, Booz Allen Hamilton. I put it on at NASA. The Houston Police Department has a very good video called, "Run, Hide, Fight." You've got to remember a lot of these type of shootings are grandiose suicides. That's really what they are.

REHMAll right. Caroline Hamilton, do you want to comment?

HAMILTONYes, I do. I think that I agree with him -- with the caller completely that we're not going to be able to have any legislation that's going to be more gun control. I think also some of the societal changes that you're talking about, about having people be less violent, you know, ways to look at people who are getting help with mental disorders that, you know, adjusting their medication or taking them off of it or putting them on whatever, those are just such long-range solutions that it's going to -- it would -- even if everybody in the United States decided tomorrow to do it, it would take 20 years.

HAMILTONSo that's why I think it's so important to -- an active shooting training and the "Run, Hide, Fight," that's available at DHS.gov, is great background for everybody to have, just for their personal protection. But, again, I just think we need to talk about, what kind of protective controls can we put in place in 2014 to protect a lot of people from having this happen again?

REHMAll right. And here's an email from Tammy, which says, "At what point do we say too much is enough? Do we put metal detectors in New York City Times Square? Do we create checkpoints before entering any highly populated metropolitan area? How do you stop an irrational act by an atypical random individual? Is not this a small risk to take in order to ensure we all maintain our civil liberties? Why must we all sacrifice liberties for which many fought and died, just to protect the irrational fears of a few individuals?" Tom Nolan, what's your thought?

NOLANI mean, in response to the first part of the question, the answer is you can't. And you don't stop these individuals who are acting irrationally, who are intending to do us harm. There are -- I don't think any number of checkpoints or searches or any kind of electronic surveillance is going to deter determined individuals from doing us harm, if they are intending to do so.

NOLANI mean we have now, in Boston, where I'm based, we have random searches on public transportation where everyone who enters a certain station is going to be subjected to a search. And anyone who is intending on doing any harm to people on the subway will simply go to the next stop where there are no searches. So, yeah, the answer is, no. There isn't anything you can do, I think, to deter determined individuals from causing us harm.

REHMAll right. So, Caroline Hamilton, if you were advising the Boston Police at this point in terms of the risk and how to assess it, how to prevent any violence from occurring, how would you do it?

HAMILTONWell, the first thing I'd do is I'd have some access control points that people come through. And so you don't have to have -- open up every single person's bag. You can screen them up front and get them in. And the other thing -- and partly in response to the last caller -- was, you know, there -- technology's really gone a long way with security controls now.

HAMILTONSo one of the things that I think might have helped in the Franklin High School event was faster response duress alarms -- panic alarms. It's one of the things that went wrong at the LAX shooting was that they had a panic alarm, and it wasn't working. Or nobody knew where it was. But I think that there are some things like that that -- and pick up the Washington Navy Yard Shooting where we were able to go back to the cameras later and see the guy coming out of the bathroom with a gun.

HAMILTONBut the cameras weren't monitored at the time, so they couldn't see that. So they couldn't block the end of the hall and prevent him from going further into the buildings. So I think a lot of it is taking a little -- a little more protective approach, a little more risk-based approach...

REHMAh.

HAMILTON...a little more risk-based approach, and especially on large events, where you know they're going to be a natural target. And we have a list, the FBI has a list of those, DHS has a list of those, and high-value "targets" and doing some -- a little better protecting controls in those and also having not only metal screening -- maybe for schools if it's necessary, especially in high-risk neighborhoods -- but also having panic alarm, faster notification. You know, now, at a shooting, if somebody gets there -- if the officers respond in two minutes, it's too late. They've already killed 25 people.

REHMCaroline Hamilton, she's a threat and risk assessment expert. And we also have Bruce Shapiro from Columbia University, Liza Gold at Georgetown University, and Thomas Nolan, chair of the Department of Criminal Justice at State University of New York at Plattsburgh. And you're listening to "The Diane Rehm Show." Going to take a call. There are several emails asking about the role of social media on the number of attacks. Does the Internet foment some of the intensity of feelings or rationalization of these attackers? Bruce Shapiro.

SHAPIROThere's not a lot of good data on this. I think we know that the Internet is a very fertile ground for very angry minds. And we know that someone like Anders Behring Breivik in Norway spent a lot of time connecting with other -- with hate groups and racists on the Internet.

SHAPIROSo for that kind of violence, organized violence, I think we can say the Internet has a role. For someone like an Adam Lanza, who is living in a world of his own, from what we can tell, I don't think we really know. The crucial role of social media though is when these events happen. So often, wrong information now gets out so quickly...

REHMAh.

SHAPIRO...that myths about what they are about are borne in an instant. And I think that is something we need to pay attention to.

REHMThomas Nolan, what advice would you give to those individuals planning to attend the Boston Marathon next week?

NOLANWell, be cognizant of the very real presence of a massive police presence, of a huge number of police officers and, to the extent that you can, enjoy the event as it's been carried out in past years.

REHMAnd what about you, Liza Gold?

GOLDWell, I would say that in -- Bruce mentioned Northern Ireland. Israel is another example. There are many examples of countries, states, that understand that there is a risk of violence -- a heightened risk of violence. And I think we all should -- for example, the Times Square bomb that was found by somebody who was just being alert -- be alert. If you see something, tell somebody.

REHMSay something.

GOLDYeah.

REHMAnd, Caroline Hamilton, lastly to you. What would you say to those individuals going to the Boston Marathon? Very briefly.

HAMILTONSituational awareness. Know where you are. Know what's around you. Keep your mind open so that you can see anything that seems suspicious. Know where the police protection is. And then go out there and enjoy yourself.

REHMThank you all so much, Caroline Hamilton, Bruce Shapiro, Liza Gold, Thomas Nolan. If you see something, say something. Thanks for listening, all. I'm Diane Rehm.