Who attacked the Boston Marathon?

This is a rush transcript from "Hannity," April 15, 2013. This copy may not be in its final form and may be updated.

SEAN HANNITY, HOST: As we reported earlier tonight, we do not know if those responsible for today's deadly bombings in Boston were domestic or foreign.

Joining me now is someone who knows all too well about those who want to harm and kill Americans. He is the nation's very first secretary of Homeland Security, Governor Tom Ridge. Welcome back to the program, sir. I wish it were under better circumstances, of course.

TOM RIDGE, FORMER HOMELAND SECURITY SECRETARY: So do I.

HANNITY: You know, we always say it, maybe it sounds cliched, Governor, Mr. Secretary, but I have to tell you we have to be right 100 percent of the time.

RIDGE: That's exactly right.

HANNITY: This is how vulnerable, it reminds us how vulnerable we can be.

RIDGE: Sean, you are spot on. I mean, we have to be right all the time. I think Mark Fuhrman and some of the other guests have alluded to another notion that I think is very important for your audience and the rest of the country to understand.

We have a tendency in a just in time world in the United States of America to look at our watches. We have watches and they have time. Every day goes by we have been very fortunate for almost 10 years with the exception of Fort Hood and a couple other events, but we've been very fortunate.

This is a global surge and sadly it's a reality we have to deal with. In spite of all the efforts, and I'm confident that they did everything they could to secure as best they could 26-plus miles.

But at the end of the day, you and I both know there are multiple events with thousands, if not hundreds of thousands of people all around this country, open spaces, stadiums, gymnasium, it's a target-rich environment for the terrorists.

We've been waiting for a long time for the next incident, and tragically it just happened today in Boston.

HANNITY: Governor, what do you glean from the information that we do have at this hour? What do you glean from the fact there was about a 14- second interval before the second bomb went off?

What do you glean from the fact that there were other devices that were, thankfully, found by the police department and they were able to detonate them? Does it fit any one pattern of any group? I know it is speculation, but --

RIDGE: Sure. First of all, I want to compliment you, you said we have more questions than answers and I think that's important. We don't want to answer our own questions until we get more information.

My view has changed just even in the past couple hours. We know it was a rudimentary, fundamental device. Mark Fuhrman said you can probably make a similar device with ingredients from your own home. But at one time it was two devices and one two undetonated now there may be as many as five.

Then the question becomes is there one person involved? Unlikely, now it seems coordinated. How many, we don't know. And what is the detonating device? Obviously, there was a delay and if there were five others that were undetonated.

That may be in terms of evidence and turning a finger of responsibility one of the most significant clues that the law enforcement community can come up with.

HANNITY: Do we know for a fact it was on a timer or a delay or could it have potentially, like what our military is dealing with in the field in Iraq and Afghanistan, could it be triggered by a cell phone, which I think very wisely the law enforcement turned off for a while in Boston.

RIDGE: They were at the ready. They knew that was a potential means to detonate the other devices. That shows you how conclude into that notion and that's why they told everybody to stay off the cell phones. It's difficult.

These are anti-personnel devices. They will kill a few people, but maximum severe personal injury. As you and I are talking now there are probably dozens and hundreds of people in surgery, amputations and it's designed for that purpose.

And if it's confirmed there were at least five other devices on this route or elsewhere suggest a coordinated attack. The detonating device had to be fairly sophisticated so you think more a relationship between the group responsible over this and probably something bigger than a domestic plot, maybe associated a broader international Jihadist organization.

HANNITY: How do you interpret, Mr. Secretary, the police are telling us there's no suspect at the hospital, but there are a few people we are talking to and all day long the terminology was there is a person of interest. My interpretation of it as a lay man, they have somebody that perhaps they saw on video with backpacks that they are suspicious of?

RIDGE: I believe that that term is used and I've heard it used a couple times and I can only tell you the context within which I heard it and how it was used, pointing to someone they thought may have been responsible or have knowledge of the incident, if not responsible.

Generally, it is directed toward sun they think that may be responsible or for the incident, but it's so difficult. In the PC world nobody wants to say anything. By the way I don't blame them right now. We are four hours after the incident. The police are scrambling. You have more resources down there.

I don't imagine the public could ever truly appreciate the hundreds of people that are working this issue right any. Not just the police within the city, but the state police, the FBI. There are probably hundreds, if not thousands of people following leads as you and I are having this conversation.

Again, at the outset you did the right thing, a lot of questions, not too many answers. Let's fill in the gaps with facts.

HANNITY: I think we will. Certainly, there are thing we can learn from each instance. One of the things we learned on 9/11, as you learned well, is that Al Qaeda, for example, works in waves.

That is they want multiple attacks at one time to create the maximum amount of chaos. Some said there seems to be similarities between the London and Madrid bombings, Mr. Secretary. There are certain patterns you put together with certain groups and some people are more likely to claim credit than others?

RIDGE: We are waiting to go see if somebody claims credit. But you are right, the Madrid bombings and the bombings in '05 in London, multiple attacks in public places, there one was the underground and the other was the public transportation system in Madrid.

So you get a sense, as we find out more and more information about more and more explosive devices, the delay between the first explosion and the second. Once we know about the detonating device, it has to be for sophisticated than some of us perhaps thought initially.

That it's morph a coordinated attack than any of us may have thought after the first hour of the incident.

HANNITY: One more question, additional officers immediately were sent out to prominent location necessary the city of New York. We also know in D.C. that the Secret Service shut down Pennsylvania Avenue. Obviously, the nation is on high alert and will stay on high alert. What period of time do you think needs to pass until things, at least in law enforcement's mind, begin to slow down and calm down?

RIDGE: Number one, I think it's appropriate at certain venues, we ramp up. It's been embedded into our system for 10 years. I think they will start to stand down when they get information that enables them to stand down. Right now, I think appropriate safety and security measures have been taken.

I think it's very appropriate they have done so, and I can't give you a time frame. It may be a day, it may be a week. But tell only stand down when they have information that allows them to pull back some of the security protocols they have embedded in the past 45 hours.

HANNITY: And there are a lot of sick, evil, twisted people and whoever did this designed to inflict the most damage, maximum damage and harm to very innocent people. We need to get to the bottom of it. Thank you, sir, for being with us.

RIDGE: Thanks, Sean.

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